1.
Iron(II) oxide
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Iron oxide or ferrous oxide is the inorganic compound with the formula FeO. Its mineral form is known as wüstite, one of several iron oxides, it is a black-colored powder that is sometimes confused with rust, which consists of hydrated iron oxide. Iron oxide also refers to a family of related non-stoichiometric compounds, FeO can be prepared by the thermal decomposition of iron oxalate. FeC2O4 → FeO + CO2 + CO The procedure is conducted under an atmosphere to avoid the formation of ferric oxide. A similar procedure can also be used for the synthesis of manganous oxide, stoichiometric FeO can be prepared by heating Fe0. 95O with metallic iron at 770 °C and 36 kbar. Below 200 K there is a change to the structure which changes the symmetry to rhombohedral. Iron oxide makes up approximately 9% of the Earths mantle, within the mantle, it may be electrically conductive, which is a possible explanation for perturbations in Earths rotation not accounted for by accepted models of the mantles properties. Iron oxide is used as a pigment and it is FDA-approved for use in cosmetics and it is used in some tattoo inks. It can also be used as a phosphate remover from home aquaria
2.
Chemistry
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Chemistry is a branch of physical science that studies the composition, structure, properties and change of matter. Chemistry is sometimes called the science because it bridges other natural sciences, including physics. For the differences between chemistry and physics see comparison of chemistry and physics, the history of chemistry can be traced to alchemy, which had been practiced for several millennia in various parts of the world. The word chemistry comes from alchemy, which referred to a set of practices that encompassed elements of chemistry, metallurgy, philosophy, astrology, astronomy, mysticism. An alchemist was called a chemist in popular speech, and later the suffix -ry was added to this to describe the art of the chemist as chemistry, the modern word alchemy in turn is derived from the Arabic word al-kīmīā. In origin, the term is borrowed from the Greek χημία or χημεία and this may have Egyptian origins since al-kīmīā is derived from the Greek χημία, which is in turn derived from the word Chemi or Kimi, which is the ancient name of Egypt in Egyptian. Alternately, al-kīmīā may derive from χημεία, meaning cast together, in retrospect, the definition of chemistry has changed over time, as new discoveries and theories add to the functionality of the science. The term chymistry, in the view of noted scientist Robert Boyle in 1661, in 1837, Jean-Baptiste Dumas considered the word chemistry to refer to the science concerned with the laws and effects of molecular forces. More recently, in 1998, Professor Raymond Chang broadened the definition of chemistry to mean the study of matter, early civilizations, such as the Egyptians Babylonians, Indians amassed practical knowledge concerning the arts of metallurgy, pottery and dyes, but didnt develop a systematic theory. Greek atomism dates back to 440 BC, arising in works by such as Democritus and Epicurus. In 50 BC, the Roman philosopher Lucretius expanded upon the theory in his book De rerum natura, unlike modern concepts of science, Greek atomism was purely philosophical in nature, with little concern for empirical observations and no concern for chemical experiments. Work, particularly the development of distillation, continued in the early Byzantine period with the most famous practitioner being the 4th century Greek-Egyptian Zosimos of Panopolis. He formulated Boyles law, rejected the four elements and proposed a mechanistic alternative of atoms. Before his work, though, many important discoveries had been made, the Scottish chemist Joseph Black and the Dutchman J. B. English scientist John Dalton proposed the theory of atoms, that all substances are composed of indivisible atoms of matter. Davy discovered nine new elements including the alkali metals by extracting them from their oxides with electric current, british William Prout first proposed ordering all the elements by their atomic weight as all atoms had a weight that was an exact multiple of the atomic weight of hydrogen. The inert gases, later called the noble gases were discovered by William Ramsay in collaboration with Lord Rayleigh at the end of the century, thereby filling in the basic structure of the table. Organic chemistry was developed by Justus von Liebig and others, following Friedrich Wöhlers synthesis of urea which proved that organisms were, in theory
3.
Iron
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Iron is a chemical element with symbol Fe and atomic number 26. It is a metal in the first transition series and it is by mass the most common element on Earth, forming much of Earths outer and inner core. It is the fourth most common element in the Earths crust, like the other group 8 elements, ruthenium and osmium, iron exists in a wide range of oxidation states, −2 to +6, although +2 and +3 are the most common. Elemental iron occurs in meteoroids and other low oxygen environments, but is reactive to oxygen, fresh iron surfaces appear lustrous silvery-gray, but oxidize in normal air to give hydrated iron oxides, commonly known as rust. Unlike the metals that form passivating oxide layers, iron oxides occupy more volume than the metal and thus flake off, Iron metal has been used since ancient times, although copper alloys, which have lower melting temperatures, were used even earlier in human history. Pure iron is soft, but is unobtainable by smelting because it is significantly hardened and strengthened by impurities, in particular carbon. A certain proportion of carbon steel, which may be up to 1000 times harder than pure iron. Crude iron metal is produced in blast furnaces, where ore is reduced by coke to pig iron, further refinement with oxygen reduces the carbon content to the correct proportion to make steel. Steels and iron alloys formed with metals are by far the most common industrial metals because they have a great range of desirable properties. Iron chemical compounds have many uses, Iron oxide mixed with aluminium powder can be ignited to create a thermite reaction, used in welding and purifying ores. Iron forms binary compounds with the halogens and the chalcogens, among its organometallic compounds is ferrocene, the first sandwich compound discovered. Iron plays an important role in biology, forming complexes with oxygen in hemoglobin and myoglobin. Iron is also the metal at the site of many important redox enzymes dealing with cellular respiration and oxidation and reduction in plants. A human male of average height has about 4 grams of iron in his body and this iron is distributed throughout the body in hemoglobin, tissues, muscles, bone marrow, blood proteins, enzymes, ferritin, hemosiderin, and transport in plasma. The mechanical properties of iron and its alloys can be evaluated using a variety of tests, including the Brinell test, Rockwell test, the data on iron is so consistent that it is often used to calibrate measurements or to compare tests. An increase in the content will cause a significant increase in the hardness. Maximum hardness of 65 Rc is achieved with a 0. 6% carbon content, because of the softness of iron, it is much easier to work with than its heavier congeners ruthenium and osmium. Because of its significance for planetary cores, the properties of iron at high pressures and temperatures have also been studied extensively
4.
Oxidation state
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The oxidation state, often called the oxidation number, is an indicator of the degree of oxidation of an atom in a chemical compound. This is never exactly true for real bonds, the term oxidation was first used by Lavoisier to signify reaction of a substance with oxygen. Much later, it was realized that the substance, upon being oxidized, loses electrons, oxidation states are typically represented by integers. In some cases, the oxidation state of an element is a fraction. It is predicted that even a +10 oxidation state may be achieveable by platinum in the platinum tetroxide dication, the increase in oxidation state of an atom, through a chemical reaction, is known as an oxidation, a decrease in oxidation state is known as a reduction. Such reactions involve the transfer of electrons, a net gain in electrons being a reduction. For pure elements, the state is zero. There are various methods for determining oxidation states, in inorganic nomenclature, the oxidation state is determined and expressed as an oxidation number, and is represented by a Roman numeral placed after the element name. In coordination chemistry, oxidation number is defined differently from oxidation state, a “Comprehensive definition of oxidation state ” has been published with free access. This article is a distillation of an IUPAC technical report Toward a comprehensive definition of oxidation state. Exceptions to this are that hydrogen has a state of −1 in hydrides of active metals, e. g. LiH. There are two different methods for determining the state of elements in chemical compounds. First a method based on the rules in the IUPAC definition, second, a method based on the relative electronegativity of the elements in the compound, where the more electronegative element is assumed to take the negative charge. Any pure element—even if it forms diatomic molecules like chlorine —has an oxidation state of zero, examples of this are Cu or O2. For monatomic ions, the state is the same as the charge of the ion. For example, the anion has an oxidation state of −2. The sum of oxidation states for all atoms in a molecule or polyatomic ion is equal to the charge of the molecule or ion, thus, the oxidation state of one element can be calculated from the oxidation states of the other elements. An application of this rule is that the sum of the states of all atoms in a neutral molecule must be zero
5.
Ferric
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Ferric refers to iron-containing materials or compounds. In chemistry the term is reserved for iron with an number of +3. On the other hand, ferrous refers to iron with oxidation number of +2, iron is usually the most stable form of iron in air, as illustrated by the pervasiveness of rust, an insoluble iron-containing material. The word ferric is derived from the Latin word ferrum for iron, examples include iron-sulfur clusters, oxyhemoglobin, ferritin, and the cytochromes. The bioavailability of iron is of great interest because all forms of life require iron. Iron-deficiency anemia illustrates the problems resulting from low iron intake, many foods contain soluble iron compounds and are therefore necessary for good nutrition. The low bioavailability of iron affects all forms of life, bacteria secrete iron-attracting agents called siderophores that form soluble compounds of iron that can be reabsorbed into the cell and used in building iron-containing metalloproteins. The impact of increasing the bioavailability of iron was famously demonstrated by an experiment where an area of the ocean surface was sprayed with iron salts. After several days, the phytoplankton within the treated area bloomed to such an extent that the effect was visible from outer space and this fertilizing process has been proposed as a means to mitigate the carbon dioxide content of the atmosphere. Ferric iron mitigates the eutrophication of lakes by reducing the bioavailability of phosphorus in the water, mitigation arises because ferric phosphate is insoluble. Like iron, phosphate is often a limiting nutrient, and its reduction in concentration from solution limits the growth of algae, in water, ferric iron forms compounds that are often insoluble, at least near neutral pH. A salt of ferric iron hydrolyzes water and produces iron oxide-hydroxides while contributing hydrogen ions to the solution, in contrast, typical Na+ salts dissolve in water without lowering the pH. Aluminium behaves similarly to ferric ion, rust, a mixture of ferric hydroxide compounds, illustrates the low solubility of ferric ions in water. Various reagents cause rust to dissolve even at neutral pH and these ligands include EDTA, which forms a chelate complex with the ion, displacing the hydroxide and oxide ligands that comprise rust. For this reason, EDTA is often used to iron deposits or to deliver soluble iron in fertilizers. Citrate also solubilizes ferric ion at neutral pH, although its complexes are less stable than those of EDTA, Ferric iron is a d5 center, meaning that the metal has five valence electrons in the 3d orbital shell. The magnetism of ferric compounds is determined by these five electrons. Usually ferric ions are surrounded by six ligands arranged in octahedron, sometimes three and sometimes as many as seven ligands are observed
6.
Trivalent
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In chemistry, the valence or valency of an element is a measure of its combining power with other atoms when it forms chemical compounds or molecules. The concept of valence was developed in the half of the 19th century and was successful in explaining the molecular structure of inorganic and organic compounds. The combining power or affinity of an atom of an element was determined by the number of atoms that it combined with. In methane, carbon has a valence of 4, in ammonia, nitrogen has a valence of 3, in water, oxygen has a valence of 2, and in hydrogen chloride, chlorine has a valence of 1. Chlorine, as it has a valence of one, can be substituted for hydrogen, so phosphorus has a valence of 5 in phosphorus pentachloride, PCl5. Valence diagrams of a compound represent the connectivity of the elements, examples are, Valence only describes connectivity, it does not describe the geometry of molecular compounds, or what are now known to be ionic compounds or giant covalent structures. A line between atoms does not represent a pair of electrons as it does in Lewis diagrams and this definition differs from the IUPAC definition as an element can be said to have more than one valence. It is in manner, according to Frankland, that their affinities are best satisfied. Following these examples and postulates, Frankland declares how obvious it is that This “combining power” was afterwards called quantivalence or valency. In 1857 August Kekulé proposed fixed valences for many elements, such as 4 for carbon, and used them to propose structural formulas for many organic molecules, which are still accepted today. Most 19th-century chemists defined the valence of an element as the number of its bonds without distinguishing different types of valence or of bond. For main-group elements, in 1904 Richard Abegg considered positive and negative valences, in 1916, Gilbert N. Lewis explained valence and chemical bonding in terms of a tendency of atoms to achieve a stable octet of 8 valence-shell electrons. According to Lewis, covalent bonding leads to octets by the sharing of electrons, the term covalence is attributed to Irving Langmuir, who stated in 1919 that the number of pairs of electrons which any given atom shares with the adjacent atoms is called the covalence of that atom. The prefix co- means together, so that a co-valent bond means that the share a valence. Pauling also considered hypervalent molecules, in which main-group elements have apparent valences greater than the maximal of 4 allowed by the octet rule. Similar calculations on transition-metal molecules show that the role of p orbitals is minor, so that one s, for elements in the main groups of the periodic table, the valence can vary between 1 and 7. Many elements have a common valence related to their position in the periodic table, the Latin/Greek prefixes uni-/mono-, bi-/di-, ter-/tri-, quadri-/tetra- and quinque-/penta- are used to describe ions in the charge states 1,2,3,4,5 respectively. Polyvalence or multivalence refers to species that are not restricted to a number of valence bonds
7.
IUPAC
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The International Union of Pure and Applied Chemistry /ˈaɪjuːpæk/ or /ˈjuːpæk/ is an international federation of National Adhering Organizations that represents chemists in individual countries. It is a member of the International Council for Science, IUPAC is registered in Zürich, Switzerland, and the administrative office, known as the IUPAC Secretariat, is in Research Triangle Park, North Carolina, United States. This administrative office is headed by IUPACs executive director, currently Lynn Soby, IUPAC was established in 1919 as the successor of the International Congress of Applied Chemistry for the advancement of chemistry. Its members, the National Adhering Organizations, can be national chemistry societies, national academies of sciences, there are fifty-four National Adhering Organizations and three Associate National Adhering Organizations. IUPACs Inter-divisional Committee on Nomenclature and Symbols is the world authority in developing standards for the naming of the chemical elements. Since its creation, IUPAC has been run by different committees with different responsibilities. These committees run different projects which include standardizing nomenclature, finding ways to bring chemistry to the world, IUPAC is best known for its works standardizing nomenclature in chemistry and other fields of science, but IUPAC has publications in many fields including chemistry, biology and physics. IUPAC is also known for standardizing the atomic weights of the elements through one of its oldest standing committees, the need for an international standard for chemistry was first addressed in 1860 by a committee headed by German scientist Friedrich August Kekulé von Stradonitz. This committee was the first international conference to create an international naming system for organic compounds, the ideas that were formulated in that conference evolved into the official IUPAC nomenclature of organic chemistry. IUPAC stands as a legacy of this meeting, making it one of the most important historical international collaborations of chemistry societies, since this time, IUPAC has been the official organization held with the responsibility of updating and maintaining official organic nomenclature. IUPAC as such was established in 1919, one notable country excluded from this early IUPAC is Germany. Germanys exclusion was a result of prejudice towards Germans by the Allied powers after World War I, Germany was finally admitted into IUPAC during 1929. However, Nazi Germany was removed from IUPAC during World War II, during World War II, IUPAC was affiliated with the Allied powers, but had little involvement during the war effort itself. After the war, East and West Germany were eventually readmitted to IUPAC, since World War II, IUPAC has been focused on standardizing nomenclature and methods in science without interruption. In 2016, IUPAC denounced the use of chlorine as a chemical weapon, the letter stated, Our organizations deplore the use of chlorine in this manner. According to the CWC, the use, stockpiling, distribution, IUPAC is governed by several committees that all have different responsibilities. Each committee is made up of members of different National Adhering Organizations from different countries, the steering committee hierarchy for IUPAC is as follows, All committees have an allotted budget to which they must adhere. Any committee may start a project, if a projects spending becomes too much for a committee to continue funding, it must take the issue to the Project Committee
8.
Iron(III) oxide
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Iron oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the two being iron oxide, which is rare, and iron oxide, which also occurs naturally as the mineral magnetite. As the mineral known as hematite, Fe2O3 is the source of iron for the steel industry. Fe2O3 is ferromagnetic, dark red, and readily attacked by acids, Iron oxide is often called rust, and to some extent this label is useful, because rust shares several properties and has a similar composition. To a chemist, rust is considered a material, described as hydrated ferric oxide. Fe2O3 can be obtained in various polymorphs, in the main ones, α and γ, iron adopts octahedral coordination geometry. That is, each Fe center is bound to six oxygen ligands, α-Fe2O3 has the rhombohedral, corundum structure and is the most common form. It occurs naturally as the mineral hematite which is mined as the ore of iron. It is antiferromagnetic below ~260 K, and exhibits weak ferromagnetism between 260 K and the Néel temperature,950 K and it is easy to prepare using both thermal decomposition and precipitation in the liquid phase. Its magnetic properties are dependent on many factors, e. g. pressure, particle size and it is metastable and converted from the alpha phase at high temperatures. It occurs naturally as the mineral maghemite and it is ferromagnetic and finds application in recording tapes, although ultrafine particles smaller than 10 nanometers are superparamagnetic. It can be prepared by thermal dehydratation of gamma iron oxide-hydroxide, another method involves the careful oxidation of Fe3O4. The ultrafine particles can be prepared by decomposition of iron oxalate. Several other phases have been identified or claimed, the β-phase is cubic body centered, metastable, and at temperatures above 500 °C converts to alpha phase. It can be prepared by reduction of hematite by carbon, pyrolysis of iron chloride solution, the epsilon phase is rhombic, and shows properties intermediate between alpha and gamma, and may have useful magnetic properties. Preparation of the pure epsilon phase has proven challenging due to contamination with alpha. Material with a proportion of epsilon phase can be prepared by thermal transformation of the gamma phase. This phase is metastable, transforming to the alpha phase at between 500 and 750 °C
9.
Pourbaix diagram
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In chemistry, a Pourbaix diagram, also known as a potential/pH diagram, EH-pH diagram or a pE/pH diagram, maps out possible stable phases of an aqueous electrochemical system. Predominant ion boundaries are represented by lines, as such a Pourbaix diagram can be read much like a standard phase diagram with a different set of axes. Similarly to phase diagrams, they do not allow for reaction rate or kinetic effects, the diagrams are named after Marcel Pourbaix, the Russian-born, Belgian chemist who invented them. Pourbaix diagrams are also known as EH-pH diagrams due to the labeling of the two axes, the vertical axis is labeled EH for the voltage potential with respect to the standard hydrogen electrode as calculated by the Nernst equation. The H stands for hydrogen, although other standards may be used, E H = E0 −0.0592 n log c d a b The horizontal axis is labeled pH for the -log function of the H+ ion activity. PH = − log 10 = log 10 The lines in the Pourbaix diagram show the conditions, that is. On either side of the line, one form of the species will instead be said to be predominant, in order to draw the position of the lines with the Nernst equation, the activity of the chemical species at equilibrium must be defined. Usually, the activity of a species is approximated as equal to the concentration or partial pressure, the same values should be used for all species present in the system. For soluble species, the lines are drawn for concentrations of 1 M or 10−6 M. Sometimes additional lines are drawn for other concentrations, while such diagrams can be drawn for any chemical system, it is important to note that the addition of a metal binding agent will often modify the diagram. For instance, carbonate has an effect upon the diagram for uranium. The presence of trace amounts of species such as chloride ions can also greatly affect the stability of certain species by destroying passivating layers. In addition, changes in temperature and concentration of solvated ions in solution will shift the lines in accordance with the Nernst equation. The diagrams also do not take kinetic effects into account, meaning that species shown as unstable might not react to any significant degree in practice, a simplified Pourbaix diagram indicates regions of Immunity, Corrosion and Passivity, instead of the stable species. They thus give a guide to the stability of a metal in a specific environment. Immunity means that the metal is not attacked, while corrosion shows that general attack will occur, the equation must be balanced for M, H, O and charge. A standard Gibbs free energy ΔGo is associated with each equation, a base-balanced equation can be converted to an acid-balanced equation using the equlibrium constant for the self-ionization of water, and only acid-balanced equations are considered below. In the following, the Nernst slope ∆=RT/F is used, which has a value of 0.02569, when base-10 logarithms are used, ∆λ =0.05916
10.
Latin
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Latin is a classical language belonging to the Italic branch of the Indo-European languages. The Latin alphabet is derived from the Etruscan and Greek alphabets, Latin was originally spoken in Latium, in the Italian Peninsula. Through the power of the Roman Republic, it became the dominant language, Vulgar Latin developed into the Romance languages, such as Italian, Portuguese, Spanish, French, and Romanian. Latin, Italian and French have contributed many words to the English language, Latin and Ancient Greek roots are used in theology, biology, and medicine. By the late Roman Republic, Old Latin had been standardised into Classical Latin, Vulgar Latin was the colloquial form spoken during the same time and attested in inscriptions and the works of comic playwrights like Plautus and Terence. Late Latin is the language from the 3rd century. Later, Early Modern Latin and Modern Latin evolved, Latin was used as the language of international communication, scholarship, and science until well into the 18th century, when it began to be supplanted by vernaculars. Ecclesiastical Latin remains the language of the Holy See and the Roman Rite of the Catholic Church. Today, many students, scholars and members of the Catholic clergy speak Latin fluently and it is taught in primary, secondary and postsecondary educational institutions around the world. The language has been passed down through various forms, some inscriptions have been published in an internationally agreed, monumental, multivolume series, the Corpus Inscriptionum Latinarum. Authors and publishers vary, but the format is about the same, volumes detailing inscriptions with a critical apparatus stating the provenance, the reading and interpretation of these inscriptions is the subject matter of the field of epigraphy. The works of several hundred ancient authors who wrote in Latin have survived in whole or in part and they are in part the subject matter of the field of classics. The Cat in the Hat, and a book of fairy tales, additional resources include phrasebooks and resources for rendering everyday phrases and concepts into Latin, such as Meissners Latin Phrasebook. The Latin influence in English has been significant at all stages of its insular development. From the 16th to the 18th centuries, English writers cobbled together huge numbers of new words from Latin and Greek words, dubbed inkhorn terms, as if they had spilled from a pot of ink. Many of these words were used once by the author and then forgotten, many of the most common polysyllabic English words are of Latin origin through the medium of Old French. Romance words make respectively 59%, 20% and 14% of English, German and those figures can rise dramatically when only non-compound and non-derived words are included. Accordingly, Romance words make roughly 35% of the vocabulary of Dutch, Roman engineering had the same effect on scientific terminology as a whole
11.
Steel
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Steel is an alloy of iron and other elements, primarily carbon, that is widely used in construction and other applications because of its high tensile strength and low cost. Steels base metal is iron, which is able to take on two forms, body centered cubic and face centered cubic, depending on its temperature. It is the interaction of those allotropes with the elements, primarily carbon. In the body-centred cubic arrangement, there is an atom in the centre of each cube. Carbon, other elements, and inclusions within iron act as hardening agents that prevent the movement of dislocations that otherwise occur in the lattices of iron atoms. The carbon in steel alloys may contribute up to 2. 1% of its weight. Steels strength compared to pure iron is possible at the expense of irons ductility. With the invention of the Bessemer process in the mid-19th century and this was followed by Siemens-Martin process and then Gilchrist-Thomas process that refined the quality of steel. With their introductions, mild steel replaced wrought iron, further refinements in the process, such as basic oxygen steelmaking, largely replaced earlier methods by further lowering the cost of production and increasing the quality of the product. Today, steel is one of the most common materials in the world and it is a major component in buildings, infrastructure, tools, ships, automobiles, machines, appliances, and weapons. Modern steel is generally identified by various grades defined by assorted standards organizations, the noun steel originates from the Proto-Germanic adjective stakhlijan, which is related to stakhla. The carbon content of steel is between 0. 002% and 2. 1% by weight for plain iron–carbon alloys and these values vary depending on alloying elements such as manganese, chromium, nickel, iron, tungsten, carbon and so on. Basically, steel is an alloy that does not undergo eutectic reaction. In contrast, cast iron does undergo eutectic reaction, too little carbon content leaves iron quite soft, ductile, and weak. Carbon contents higher than those of steel make an alloy, commonly called pig iron, while iron alloyed with carbon is called carbon steel, alloy steel is steel to which other alloying elements have been intentionally added to modify the characteristics of steel. Common alloying elements include, manganese, nickel, chromium, molybdenum, boron, titanium, vanadium, tungsten, cobalt, and niobium. Additional elements are important in steel, phosphorus, sulfur, silicon, and traces of oxygen, nitrogen, and copper. Alloys with a higher than 2. 1% carbon content, depending on other element content, cast iron is not malleable even when hot, but it can be formed by casting as it has a lower melting point than steel and good castability properties
12.
Pig iron
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Pig iron is an intermediate product of the iron industry. Pig iron is made by smelting iron ore into an ingot of impure high carbon-content iron in a blast furnace as an ingredient for further processing steps. When the metal had cooled and hardened, the ingots were simply broken from the runner. As pig iron is intended for remelting, the size of the ingots. Smelting and producing pig iron and other products was known to the Ancient Egyptians. The Roman Empire and later the Muslim caliphates of the Middle Ages inherited and refined these technologies, because of the collapse of the Western Roman Empire, Western Europe did not rediscover the process until the Late Middle Ages. The phase transition of the iron into liquid in the furnace was an avoided phenomenon, the Chinese were also making pig iron by the later Zhou Dynasty. Traditionally pig iron was worked into wrought iron in forges, later puddling furnaces. In these processes, pig iron is melted and a current of air is directed over it while it is stirred or agitated. This causes the dissolved impurities to be thoroughly oxidized, an intermediate product of puddling is known as refined pig iron, finers metal, or refined iron. Pig iron can also be used to produce gray iron and this is achieved by remelting pig iron, often along with substantial quantities of steel and scrap iron, removing undesirable contaminants, adding alloys, and adjusting the carbon content. Some pig iron grades are suitable for producing ductile iron and these are high purity pig irons and depending on the grade of ductile iron being produced these pig irons may be low in the elements silicon, manganese, sulfur and phosphorus. These types of pig irons are used to all the elements in a ductile iron charge which may be harmful to the ductile iron process. Earlier processes for this included the finery forge, the furnace, the Bessemer process. Modern pig casting machines produce stick pigs, which break into smaller 4–10 kg piglets at discharge
13.
Alloy
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An alloy is a mixture of metals or a mixture of a metal and another element. Alloys are defined by a metallic bonding character, an alloy may be a solid solution of metal elements or a mixture of metallic phases. Intermetallic compounds are alloys with a stoichiometry and crystal structure. Zintl phases are sometimes considered alloys depending on bond types. Alloys are used in a variety of applications. In some cases, a combination of metals may reduce the overall cost of the material while preserving important properties, in other cases, the combination of metals imparts synergistic properties to the constituent metal elements such as corrosion resistance or mechanical strength. Examples of alloys are steel, solder, brass, pewter, duralumin, bronze, the alloy constituents are usually measured by mass. Alloys are usually classified as substitutional or interstitial alloys, depending on the arrangement that forms the alloy. They can be classified as homogeneous, or heterogeneous or intermetallic. An alloy is a mixture of elements, which forms an impure substance that retains the characteristics of a metal. Alloys are made by mixing two or more elements, at least one of which is a metal and this is usually called the primary metal or the base metal, and the name of this metal may also be the name of the alloy. The other constituents may or may not be metals but, when mixed with the base, they will be soluble. The mechanical properties of alloys will often be different from those of its individual constituents. A metal that is very soft, such as aluminium, can be altered by alloying it with another soft metal. Although both metals are soft and ductile, the resulting aluminium alloy will have much greater strength. Adding a small amount of carbon to iron trades its great ductility for the greater strength of an alloy called steel. Due to its strength, but still substantial toughness, and its ability to be greatly altered by heat treatment, steel is one of the most useful. By adding chromium to steel, its resistance to corrosion can be enhanced, creating stainless steel, while adding silicon will alter its electrical characteristics, producing silicon steel
14.
Metal
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A metal is a material that is typically hard, opaque, shiny, and has good electrical and thermal conductivity. Metals are generally malleable—that is, they can be hammered or pressed permanently out of shape without breaking or cracking—as well as fusible and ductile, about 91 of the 118 elements in the periodic table are metals, the others are nonmetals or metalloids. Some elements appear in both metallic and non-metallic forms, astrophysicists use the term metal to collectively describe all elements other than hydrogen and helium, the simplest two, in a star. The star fuses smaller atoms, mostly hydrogen and helium, to larger ones over its lifetime. In that sense, the metallicity of an object is the proportion of its matter made up of all chemical elements. Many elements and compounds that are not normally classified as metals become metallic under high pressures, the atoms of metallic substances are typically arranged in one of three common crystal structures, namely body-centered cubic, face-centered cubic, and hexagonal close-packed. In bcc, each atom is positioned at the center of a cube of eight others, in fcc and hcp, each atom is surrounded by twelve others, but the stacking of the layers differs. Some metals adopt different structures depending on the temperature, atoms of metals readily lose their outer shell electrons, resulting in a free flowing cloud of electrons within their otherwise solid arrangement. This provides the ability of metallic substances to easily transmit heat, while this flow of electrons occurs, the solid characteristic of the metal is produced by electrostatic interactions between each atom and the electron cloud. This type of bond is called a metallic bond, Metals are usually inclined to form cations through electron loss, reacting with oxygen in the air to form oxides over various timescales. Examples,4 Na + O2 →2 Na2O2 Ca + O2 →2 CaO4 Al +3 O2 →2 Al2O3, the transition metals are slower to oxidize because they form a passivating layer of oxide that protects the interior. Others, like palladium, platinum and gold, do not react with the atmosphere at all, some metals form a barrier layer of oxide on their surface which cannot be penetrated by further oxygen molecules and thus retain their shiny appearance and good conductivity for many decades. The oxides of metals are generally basic, as opposed to those of nonmetals, exceptions are largely oxides with very high oxidation states such as CrO3, Mn2O7, and OsO4, which have strictly acidic reactions. Painting, anodizing or plating metals are good ways to prevent their corrosion, however, a more reactive metal in the electrochemical series must be chosen for coating, especially when chipping of the coating is expected. Water and the two form an electrochemical cell, and if the coating is less reactive than the coatee. Metals in general have high conductivity, high thermal conductivity. Typically they are malleable and ductile, deforming under stress without cleaving, in terms of optical properties, metals are shiny and lustrous. Sheets of metal beyond a few micrometres in thickness appear opaque, although most metals have higher densities than most nonmetals, there is wide variation in their densities, lithium being the least dense solid element and osmium the densest
15.
Ferromagnetism
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Not to be confused with Ferrimagnetism, for an overview see Magnetism. Ferromagnetism is the mechanism by which certain materials form permanent magnets. In physics, several different types of magnetism are distinguished, an everyday example of ferromagnetism is a refrigerator magnet used to hold notes on a refrigerator door. The attraction between a magnet and ferromagnetic material is the quality of magnetism first apparent to the ancient world, permanent magnets are either ferromagnetic or ferrimagnetic, as are the materials that are noticeably attracted to them. Only a few substances are ferromagnetic, the common ones are iron, nickel, cobalt and most of their alloys, some compounds of rare earth metals, and a few naturally occurring minerals, including some varieties of lodestone. Historically, the term ferromagnetism was used for any material that could exhibit spontaneous magnetization and this general definition is still in common use. In particular, a material is ferromagnetic in this sense only if all of its magnetic ions add a positive contribution to the net magnetization. If some of the magnetic ions subtract from the net magnetization, if the moments of the aligned and anti-aligned ions balance completely so as to have zero net magnetization, despite the magnetic ordering, then it is an antiferromagnet. These alignment effects only occur at temperatures below a critical temperature. Among the first investigations of ferromagnetism are the works of Aleksandr Stoletov on measurement of the magnetic permeability of ferromagnetics. The table on the right lists a selection of ferromagnetic and ferrimagnetic compounds, ferromagnetism is a property not just of the chemical make-up of a material, but of its crystalline structure and microstructure. There are ferromagnetic metal alloys whose constituents are not themselves ferromagnetic, called Heusler alloys, conversely there are non-magnetic alloys, such as types of stainless steel, composed almost exclusively of ferromagnetic metals. Amorphous ferromagnetic metallic alloys can be made by rapid quenching of a liquid alloy. These have the advantage that their properties are isotropic, this results in low coercivity, low hysteresis loss, high permeability. One such typical material is a transition metal-metalloid alloy, made from about 80% transition metal, a relatively new class of exceptionally strong ferromagnetic materials are the rare-earth magnets. They contain lanthanide elements that are known for their ability to carry large magnetic moments in well-localized f-orbitals, a number of actinide compounds are ferromagnets at room temperature or exhibit ferromagnetism upon cooling. PuP is a paramagnet with cubic symmetry at room temperature, in its ferromagnetic state, PuPs easy axis is in the <100> direction. In NpFe2 the easy axis is <111>, above TC ≈500 K NpFe2 is also paramagnetic and cubic
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Steelmaking
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Steelmaking is the process for producing steel from iron ore and scrap. Limiting dissolved gases such as nitrogen and oxygen, and entrained impurities in the steel is also important to ensure the quality of the products cast from the liquid steel, steelmaking has existed for millennia, but it was not commercialized until the 19th century. The ancient craft process of steelmaking was the crucible process, in the 1850s and 1860s, the Bessemer process and the Siemens-Martin process turned steelmaking into a heavy industry. In recent times, EAF steelmaking technology has evolved closer to oxygen steelmaking as more energy is introduced into the process. Steelmaking has played a crucial role development of modern technological societies, cast iron is a hard brittle material that is difficult to work, whereas steel is malleable, relatively easily formed and a versatile material. For much of history, steel has only been made in small quantities. The earliest means of producing steel was in a bloomery, early modern methods of producing steel were often labour-intensive and highly skilled arts. See, finery forge, in which the German finery process could be managed to produce steel, an important aspect of the Industrial Revolution was the development of large-scale methods of producing forgeable metal. The puddling furnace was initially a means of producing wrought iron, the real revolution in steelmaking only began at the end of the 1850s when the Bessemer process became the first successful method of steelmaking in quantity, followed by the open-hearth furnace. Modern steelmaking processes can be broken into two categories, primary and secondary steelmaking, secondary steelmaking involves refining of the crude steel before casting and the various operations are normally carried out in ladles. Basic oxygen steelmaking is a method of steelmaking in which carbon-rich molten pig iron is made into steel. Blowing oxygen through molten pig iron lowers the carbon content of the alloy, the slag chemistry of the process is also controlled to ensure that impurities such as silicon and phosphorus are removed from the metal. The process was developed in 1948 by Robert Durrer and commercialized in 1952–53 by Austrian VOEST, the LD converter, named after the Austrian towns of Linz and Donawitz is a refined version of the Bessemer converter where blowing of air is replaced with blowing oxygen. It reduced capital cost of the plants, time of smelting, between 1920 and 2000, labour requirements in the industry decreased by a factor of 1,000, from more than 3 worker-hours per tonne to just 0.003. The vast majority of steel manufactured in the world is produced using the basic oxygen furnace, in 2011, it accounted for 70% of global steel output. Modern furnaces will take a charge of iron of up to 350 tons and convert it into steel in less than 40 minutes, electric arc furnace steelmaking is the manufacture of steel from scrap or direct reduced iron melted by electric arcs. In an electric arc furnace, a batch of steel may be started by loading scrap or direct reduced iron into the furnace, gas burners may be used to assist with the melt down of the scrap pile in the furnace. As in basic oxygen steelmaking, fluxes are also added to protect the lining of the vessel, electric arc furnace steelmaking typically uses furnaces of capacity around 100 tonnes that produce steel every 40 to 50 minutes for further processing
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Ferrous metal recycling
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Ferrous metals are able to be recycled, with steel being one of the most recycled materials in the world. Ferrous metals contain a percentage of iron and the addition of carbon. In the United States, steel containers, cans, automobiles, appliances, a typical appliance is about 75% steel by weight and automobiles are about 65% steel and iron. The steel industry has been actively recycling for more than 150 years and it is cheaper to recycle steel than to mine iron ore and manipulate it through the production process to form new steel. Steel does not lose any of its inherent physical properties during the recycling process, the energy saved by recycling reduces the annual energy consumption of the industry by about 75%, which is enough to power eighteen million homes for one year. Basic oxygen steelmaking uses 25–35% recycled steel to make new steel, EAF steelmaking uses almost 100% recycled steel. This steel contains greater concentrations of elements that cannot be removed through the application of oxygen. It is used to make structural beams, plates, reinforcing bar, downcycling of steel by hard-to-separate impurities such as copper or tin can only be prevented by well-aimed scrap selection or dilution by pure steel. Recycling one metric ton of steel saves 1.1 metric tons of ore,630 kilograms of coal. Also known as borings or swarf Manganese steel – Non magnetic, hardened steel used in the industry, cement mixers, rock crushers. Rails – Rail or tram tracks As of 2008, more than 83% of steel was recycled in the United States and it is the most widely recycled material, in 2000, more than 60 million metric tons were recycled. Scrap metal British Metals Recycling Association Aluminium recycling Steel Recycling Institute
18.
Iron(II) chloride
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Iron chloride, also known as ferrous chloride, is the chemical compound of formula FeCl2. It is a solid with a high melting point. The compound is white, but typical samples are often off-white, FeCl2 crystallizes from water as the greenish tetrahydrate, which is the form that is most commonly encountered in commerce and the laboratory. The compound is soluble in water, aqueous solutions of FeCl2 are highly transparent. Hydrated forms of ferrous chloride are generated by treatment of wastes from steel production with hydrochloric acid, such solutions are designated spent acid, especially when the hydrochloric acid is not completely consumed, Fe +2 HCl → FeCl2 + H2 The spent acid requires treatment before its disposal. It is also byproduct from titanium production, since some titanium ores contain iron, the dihydrate crystallizes from concentrated hydrochloric acid. Ferrous chloride is prepared by addition of iron powder to a solution of methanol. This reaction gives the methanol solvate, which upon heating in a vacuum at about 160 °C gives anhydrous FeCl2, feBr2 and FeI2 can be prepared analogously. Fe +2 HCl → FeCl2 + H2 An alternative synthesis of entails the reduction of FeCl3 with chlorobenzene,2 FeCl3 + C6H5Cl →2 FeCl2 + C6H4Cl2 + HCl FeCl2 is soluble in tetrahydrofuran. In one of two classic syntheses of ferrocene, Wilkinson generated FeCl2 by heating FeCl3 with iron powder in THF, ferric chloride decomposes to ferrous chloride at high temperatures. The dihydrate, FeCl22, is a coordination polymer, each Fe center is coordinated to four doubly bridging chloride ligands. The octahedron is completed by a pair of mutually trans aquo ligands, FeCl2 and its hydrates form complexes with many ligands. The anhydrous FeCl2 is a precursor in organometallic synthesis. Solutions of the hydrates react with two equivalents of Cl to give the salt 2. Ferrous chloride has a variety of applications, but the related compounds ferrous sulfate. Aside from use in the synthesis of iron complexes, ferrous chloride serves as a reducing flocculating agent in wastewater treatment. It is the precursor to hydrated iron oxides that are magnetic pigments, ferrous chloride is employed as a reducing agent in many organic synthesis reactions
19.
Iron(II) bromide
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Iron bromide is the chemical compound with the chemical formula FeBr2. The anhydrous compound is a yellow or brownish-colored paramagnetic solid and it is a common precursor to other iron compounds in research laboratory. Several hydrates of FeBr2 are also known, like most metal halides, FeBr2 adopts a polymeric structure consisting of isolated metal centers cross-linked with halides. It crystallizes with the CdI2 structure, featuring close-packed layers of bromide ions, the packing of the halides is slightly different from that for FeCl2, which adopts the CdCl2 motif. FeBr2 is synthesized using a solution of concentrated hydrobromic acid. Gives the methanol solvate Br2 together with hydrogen gas, heating the methanol complex in a vacuum gives pure FeBr2. Iron bromide cannot be formed by the reaction of iron and bromine, FeBr2 reacts with 2 equivalents of 4NBr to give 2FeBr4. FeBr2 reacts with bromide and bromine to form the intensely colored, FeBr2 is a weak reducing agent, as are all ferrous compounds
20.
Merriam-Webster
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Merriam-Webster, Incorporated, is an American company that publishes reference books, especially known for its dictionaries. In 1831, George and Charles Merriam founded the company as G & C Merriam Co. in Springfield, in 1843, after Noah Webster died, the company bought the rights to An American Dictionary of the English Language from Websters estate. All Merriam-Webster dictionaries trace their lineage to this source, in 1964, Encyclopædia Britannica, Inc. acquired Merriam-Webster, Inc. as a subsidiary. The company adopted its current name in 1982, in 1806, Webster published his first dictionary, A Compendious Dictionary of the English Language. In 1807 Webster started two decades of work to expand his publication into a fully comprehensive dictionary, An American Dictionary of the English Language. To help him trace the etymology of words, Webster learned 26 languages, Webster hoped to standardize American speech, since Americans in different parts of the country used somewhat different vocabularies and spelled, pronounced, and used words differently. Webster completed his dictionary during his year abroad in 1825 in Paris and his 1820s book contained 70,000 words, of which about 12,000 had never appeared in a dictionary before. He also added American words, including skunk and squash, that did not appear in British dictionaries, at the age of 70 in 1828, Webster published his dictionary, it sold poorly, with only 2,500 copies putting him in debt. However, in 1840, he published the edition in two volumes with much greater success. He shows ways that American poetry inherited Websters ideas and draws on his lexicography to develop the language, in 1843, after Websters death, George Merriam and Charles Merriam secured publishing and revision rights to the 1840 edition of the dictionary. They published a revision in 1847, which did not change any of the text but merely added new sections. This began a series of revisions that were described as being unabridged in content, in 1884 it contained 118,000 words,3000 more than any other English dictionary. With the edition of 1890, the dictionary was retitled Websters International, the Collegiate Dictionary was introduced in 1898 and the series is now in its eleventh edition. Following the publication of Websters International in 1890, two Collegiate editions were issued as abridgments of each of their Unabridged editions, with the ninth edition, the Collegiate adopted changes which distinguish it as a separate entity rather than merely an abridgment of the Third New International. Some proper names were returned to the word list, including names of Knights of the Round Table, the most notable change was the inclusion of the date of the first known citation of each word, to document its entry into the English language. The eleventh edition includes more than 225,000 definitions, a CD-ROM of the text is sometimes included. This dictionary is preferred as a source for general matters of spelling by the influential The Chicago Manual of Style, the Chicago Manual states that it normally opts for the first spelling listed. Merriam overhauled the dictionary again with the 1961 Websters Third New International under the direction of Philip B, gove, making changes that sparked public controversy
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