Soap is the term for a salt of a fatty acid or for a variety of cleansing and lubricating products produced from such a substance. Household uses for soaps include washing and other types of housekeeping, where soaps act as surfactants, emulsifying oils to enable them to be carried away by water. In industry, they are used as thickeners, components of some lubricants, precursors to catalysts. Since they are salts of fatty acids, soaps have the general formula nMn+; the major classification of soaps is determined by the identity of Mn+. When M is Na or K, the soaps are called toilet soaps, used for handwashing. Many metal dications give metallic soap; when M is Li, the result is lithium soap, used in high-performance greases. Soaps are key components of most lubricating thickeners. Greases are emulsions of calcium soap or lithium soap and mineral oil. Many other metallic soaps are useful, including those of aluminium and mixtures thereof; such soaps are used as thickeners to increase the viscosity of oils.
In ancient times, lubricating greases were made by the addition of lime to olive oil. Metal soaps are included in modern artists' oil paints formulations as a rheology modifier. Most heavy metal soaps are prepared by neutralization of purified fatty acids: 2 RCO2H + CaO → 2Ca + H2O In a domestic setting, "soap" refers to what is technically called a toilet soap, used for household and personal cleaning; when used for cleaning, soap solubilizes particles and grime, which can be separated from the article being cleaned. The insoluble oil/fat molecules become associated inside micelles, tiny spheres formed from soap molecules with polar hydrophilic groups on the outside and encasing a lipophilic pocket, which shields the oil/fat molecules from the water making it soluble. Anything, soluble will be washed away with the water; the production of toilet soaps entails saponification of fats. Triglycerides are fats. An alkaline solution induces saponification whereby the triglyceride fats first hydrolyze into salts of fatty acids.
Glycerol is liberated. The glycerin can remain in the soap product as a softening agent, although it is sometimes separated; the type of alkali metal used determines the kind of soap product. Sodium soaps, prepared from sodium hydroxide, are firm, whereas potassium soaps, derived from potassium hydroxide, are softer or liquid. Potassium hydroxide was extracted from the ashes of bracken or other plants. Lithium soaps tend to be hard; these are used in greases. For making toilet soaps, triglycerides are derived from coconut, olive, or palm oils, as well as tallow. Triglyceride is the chemical name for the triesters of fatty acids and glycerin. Tallow, i.e. rendered beef fat, is the most available triglyceride from animals. Each species offers quite different fatty acid content, resulting in soaps of distinct feel; the seed oils give softer but milder soaps. Soap made from pure olive oil, sometimes called Castile soap or Marseille soap, is reputed for its particular mildness; the term "Castile" is sometimes applied to soaps from a mixture of oils, but a high percentage of olive oil.
The earliest recorded evidence of the production of soap-like materials dates back to around 2800 BC in ancient Babylon. A formula for soap consisting of water and cassia oil was written on a Babylonian clay tablet around 2200 BC; the Ebers papyrus indicates the ancient Egyptians bathed and combined animal and vegetable oils with alkaline salts to create a soap-like substance. Egyptian documents mention. In the reign of Nabonidus, a recipe for soap consisted of uhulu and sesame "for washing the stones for the servant girls"; the word sapo, Latin for soap was borrowed from an early Germanic language and is cognate with Latin sebum, "tallow". It first appears in Pliny the Elder's account. Historia Naturalis, which discusses the manufacture of soap from tallow and ashes, but the only use he mentions for it is as a pomade for hair. Aretaeus of Cappadocia, writing in the first century AD, observes among "Celts, which are men called Gauls, those alkaline substances that are made into balls called soap".
The Romans' preferred method of cleaning the body was to massage oil into the skin and scrape away both the oil and any dirt with a strigil. The Gauls used soap made from animal fat. Zosimos of Panopolis, circa 300 AD, describes soapmaking. Galen describes soap-making using lye and prescribes washing to carry away impurities from the body and clothes; the use of soap for personal cleanliness became common in the 2nd century A. D. According to Galen, the best soaps were Germanic, soaps from Gaul were second best. A detergent similar to soap was manufactured in ancient China from the seeds of Gleditsia sinensis. Another traditional detergent is a mixture of pig pancreas and plant ash called "Zhu yi zi". True soap, made of animal fat, did not appear in China until the modern era. Soap-like detergents were not as popular as creams. Hard toilet soap with a pleasant smell was produced in the Middle East during the Islamic Golden Age, when soap-making became an established industry. Recipes for soap-making are described by Muhammad ibn Zakariya al-Razi, who gave a recipe for producing glycerine from
Borates are the name for a large number of boron-containing oxyanions. The term "borates" may refer to tetrahedral boron anions, or more loosely to chemical compounds which contain borate anions of either description. Larger borates are composed of trigonal planar BO3 or tetrahedral BO4 structural units, joined together via shared oxygen atoms and may be cyclic or linear in structure. Boron most occurs in nature as borates, such as borate minerals and borosilicates; the simplest borate anion, the orthoborate ion, 3-, is known in the solid state, for example in Ca32. In this it adopts a near trigonal planar structure, it is a structural analogue of the carbonate anion 2 -. Simple bonding theories point to the trigonal planar structure. In terms of valence bond theory the bonds are formed by using sp2 hybrid orbitals on boron; some compounds termed orthoborates do not contain the trigonal planar ion, for example gadolinium orthoborate, GdBO3 contains the polyborate 9- ion, whereas the high temperature form contains planar 3-.
All borates can be considered derivatives of boric acid, B3. Boric acid is a weak proton donor in the sense of Brønsted acid, but is a Lewis acid, i.e. it can accept an electron pair. In water, it behaves as a Lewis acid accepting the electron pair of a hydroxyl ion produced by the water autoprotolysis. So, B3 is acidic because of its reaction with OH– from water, forming the tetrahydroxyborate complex − and releasing the corresponding proton left by the water autoprotolysis: B3 + 2H2O ⇌ − + + In the presence of cis-diols such as mannitol, glucose and glycerol the pKa is lowered to about 4. At neutral pH boric acid undergoes condensation reactions to form polymeric oxyanions. Well-known polyborate anions include the triborate and pentaborate anions; the condensation reaction for the formation of tetraborate is as follows: 2 B3 + 2 − ⇌ 2- + 5 H2OThe tetraborate anion includes two tetrahedral and two trigonal boron atoms symmetrically assembled in a fused bicyclic structure. The two tetrahedral boron atoms are linked together by a common oxygen atom and each bears a negative net charge brought by the supplementary OH− groups laterally attached to them.
This intricate molecular anion exhibits three rings: two fused distorted hexagonal rings and one distorted octagonal ring. Each ring is made of a succession of alternate oxygen atoms. Boroxole rings are a common structural motif in polyborate ions; the tetraborate anion occurs in the mineral borax, as an octahydrate, Na2·8H2O. The borax chemical formula is commonly written in a more compact notation as Na2B4O7·10H2O. Sodium borate can be obtained in high purity and so can be used to make a standard solution in titrimetric analysis. A number of metal borates are known, they arise by treating boric boron oxides with metal oxides. Examples hereafter include linear chains of 2, 3 or 4 trigonal BO3 structural units, each sharing only one oxygen atom with adjacent unit: diborate 4-, found in Mg2B2O5 triborate 5-, found in CaAlB3O7 tetraborate 6-, found in Li6B4O9Metaborates, such as LiBO2 contain chains of trigonal BO3 structural units, each sharing two oxygen atoms with adjacent units, whereas NaBO2 and KBO2 contain the cyclic 2- ion.
Borosilicate glass known as pyrex, can be viewed as a silicate in which some 4- units are replaced by 5- centers, together with additional cations to compensate for the difference in valence states of Si and B. Because of this substitution leads to imperfections, the material is slow to crystallise and forms a glass with low coefficient of thermal expansion and is resistant to cracking when heated, unlike soda glass. Common borate salts include sodium metaborate, NaBO2, borax. Borax is soluble in water, so mineral deposits only occur in places with low rainfall. Extensive deposits were found in Death Valley and transported out using the famous twenty-mule teams. Deposits were found at Boron, California on the edge of the Mojave Desert; the Atacama Desert in Chile contains mineable borate concentrations. Lithium metaborate or lithium tetraborate, or a mixture of both, can be used in borate fusion sample preparation of various samples for analysis by XRF, AAS, ICP-OES, ICP-AES and ICP-MS. Borate fusion and energy dispersive X-ray fluorescence spectrometry with polarized excitation have been used in the analysis of contaminated soils.
Disodium octaborate tetrahydrate is used as fungicide. Zinc borate is used as a flame retardant. Borate esters are organic compounds which are conveniently prepared by the stoichiometric condensation reaction of boric acid with alcohols. Borax Nanochannel glass materials Porous glass Vycor glass Tris borate Suanite at webmineral Johachidolite at webmineral Non-CCA Wood Preservatives: Guide to Selected Resources - National Pesticide Information Center
The borate minerals are minerals which contain a borate anion group. The borate units may be polymerised similar to the SiO4 unit of the silicate mineral class; this results in B2O5, B3O6, B2O4 anions as well as more complex structures which include hydroxide or halogen anions. The − anion exists too. Many borate minerals, such as borax and ulexite, are salts: soft soluble, found in evaporite contexts. However, such as boracite, are hard and resistant to weathering, more similar to the silicates. There are over 100 different borate minerals. Borate minerals include: Kernite Na2B4O62·3H2O Borax Na2B4O54·8H2O Ulexite NaCaB5O66·5H2O Colemanite CaB3O43·H2O Boracite Mg3B7O13Cl Painite CaZrAl9O15 IMA-CNMNC proposes a new hierarchical scheme; this list uses it to modify the Classification of Nickel–Strunz. Abbreviations: "*" - discredited. "?" - questionable/doubtful. "REE" - Rare-earth element "PGE" - Platinum-group element 03. C Aluminofluorides, 06 Borates, 08 Vanadates, 09 Silicates: Neso: insular Soro: grouping Cyclo: ring Ino: chain Phyllo: sheet Tekto: three-dimensional framework Nickel–Strunz code scheme: NN.
XY.##x NN: Nickel–Strunz mineral class number X: Nickel–Strunz mineral division letter Y: Nickel–Strunz mineral family letter ##x: Nickel–Strunz mineral/group number, x add-on letter 06. Alfredstelznerite 06. A Monoborates 06. AA BO3, without additional anions. AB BO3, with additional anions. AC B4, without and with additional anions. H Unclassified Borates 06. HA Unclassified borates: 05 Chelkarite, 10 Braitschite-, 15 Satimolite, 20 Iquiqueite, 25 Wardsmithite, 30 Korzhinskite, 35 Halurgite, 40 Ekaterinite, 45 Vitimite, 50 Canavesite, 55 Qilianshanite 06. BA Neso-diborates with double triangles B25. BB Neso-diborates with double tetrahedra B2O6. CA Neso-triborates: 10 Ameghinite, 15 Inderite, 20 Kurnakovite, 25 Inderborite, 30 Meyerhofferite, 35 Inyoite, 40 Solongoite, 45 Peprossiite-, 50 Nifontovite, 55 Olshanskyite 06. DA Neso-tetraborates: 10 Borax, 15 Tincalconite, 20 Hungchaoite. EA Neso-pentaborates: 05 Sborgite. FA Neso-hexaborates: 05 Aksaite, 10 Mcallisterite, 15 Admontite, 20 Rivadavite, 25 Teruggite 06.
BC Ino-diborates with triangles and/or tetrahedra: 10 Calciborite, 10 Aldzhanite*. CB Ino-triborates: 10 Colemanite, 15 Hydroboracite, 20 Howlite, 25 Jarandolite 06. DB Ino-tetraborates: 05 Kernite 06. EB Ino-pentaborates: 05 Larderellite, 10 Ezcurrite, 15 Probertite, 20 Tertschite, 25 Priceite 06. FB Ino-hexaborates: 05 Aristarainite, 10 Kaliborite 06. CC Phyllo-triborates: 05 Johachidolite 06. EC Phyllo-pentaborates: 05 Biringuccite, 05 Nasinite. FC Phyllo-hexaborates: 05 Nobleite, 05 Tunellite, 05 Balavinskite?. GB Phyllo-nonborates, etc.: 05 Studenitsite, 10 Penobsquisite, 15 Preobrazhenskite, 20 Walkerite 06. BD Tektodiborates with tetrahedra: 05 Santarosaite 06. DD Tekto-tetraborates: 05 Diomignite 06. ED Tekto-pentaborates: 05 IMA2007-047, 05 Tyretskite, 05 Hilgardite, 05 Kurgantaite 06. GA Tekto-heptaborates: 05 Boracite, 05 Chambersite, 05 Ericaite. GC Tekto-dodecaborates: 05 Rhodizite, 05 Londonite 06. GD Mega-tektoborates: 05 Ruitenbergite, 05 Pringleite.
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance; the reference substance for liquids is nearly always water at its densest. Nonetheless, the temperature and pressure must be specified for the reference. Pressure is nearly always 1 atm. Temperatures for both sample and reference vary from industry to industry. In British beer brewing, the practice for specific gravity as specified above is to multiply it by 1,000. Specific gravity is used in industry as a simple means of obtaining information about the concentration of solutions of various materials such as brines, antifreeze coolants, sugar solutions and acids. Being a ratio of densities, specific gravity is a dimensionless quantity; the reason for the specific gravity being dimensionless is to provide a global consistency between the U. S. and Metric Systems, since various units for density may be used such as pounds per cubic feet or grams per cubic centimeter, etc.
Specific gravity varies with pressure. Substances with a specific gravity of 1 are neutrally buoyant in water; those with SG greater than 1 are denser than water and will, disregarding surface tension effects, sink in it. Those with an SG less than 1 will float on it. In scientific work, the relationship of mass to volume is expressed directly in terms of the density of the substance under study, it is in industry where specific gravity finds wide application for historical reasons. True specific gravity can be expressed mathematically as: S G true = ρ sample ρ H 2 O where ρsample is the density of the sample and ρH2O is the density of water; the apparent specific gravity is the ratio of the weights of equal volumes of sample and water in air: S G apparent = W A, sample W A, H 2 O where WA,sample represents the weight of the sample measured in air and WA,H2O the weight of water measured in air. It can be shown that true specific gravity can be computed from different properties: S G true = ρ sample ρ H 2 O = m sample V m H 2 O V = m sample m H 2 O g g = W V, sample W V, H 2 O where g is the local acceleration due to gravity, V is the volume of the sample and of water, ρsample is the density of the sample, ρH2O is the density of water and WV represents a weight obtained in vacuum.
The density of water varies with pressure as does the density of the sample. So it is necessary to specify the temperatures and pressures at which the densities or weights were determined, it is nearly always the case. But as specific gravity refers to incompressible aqueous solutions or other incompressible substances, variations in density caused by pressure are neglected at least where apparent specific gravity is being measured. For true specific gravity calculations, air pressure must be considered. Temperatures are specified by the notation, with Ts representing the temperature at which the sample's density was determined and Tr the temperature at which the reference density is specified. For example, SG would be understood to mean that the density of the sample was determined at 20 °C and of the water at 4 °C. Taking into account different sample and reference temperatures, we note that, while SGH2O = 1.000000, it is the case that SGH2O = 0.998203⁄0.999840 = 0.998363. Here, temperature is being specified using the current ITS-90 scale and the densities used here and in the rest of this article are based on that scale.
On the previous IPTS-68 scale, the densities at 20 °C and 4 °C are 0.9982071 and 0.9999720 respective
In mathematics and chemistry, a space group is the symmetry group of a configuration in space in three dimensions. In three dimensions, there are 230 if chiral copies are considered distinct. Space groups are studied in dimensions other than 3 where they are sometimes called Bieberbach groups, are discrete cocompact groups of isometries of an oriented Euclidean space. In crystallography, space groups are called the crystallographic or Fedorov groups, represent a description of the symmetry of the crystal. A definitive source regarding 3-dimensional space groups is the International Tables for Crystallography. Space groups in 2 dimensions are the 17 wallpaper groups which have been known for several centuries, though the proof that the list was complete was only given in 1891, after the much more difficult classification of space groups had been completed. In 1879 Leonhard Sohncke listed the 65 space groups. More he listed 66 groups, but Fedorov and Schönflies both noticed that two of them were the same.
The space groups in three dimensions were first enumerated by Fedorov, shortly afterwards were independently enumerated by Schönflies. The correct list of 230 space groups was found by 1892 during correspondence between Fedorov and Schönflies. Barlow enumerated the groups with a different method, but omitted four groups though he had the correct list of 230 groups from Fedorov and Schönflies. Burckhardt describes the history of the discovery of the space groups in detail; the space groups in three dimensions are made from combinations of the 32 crystallographic point groups with the 14 Bravais lattices, each of the latter belonging to one of 7 lattice systems. This results in a space group being some combination of the translational symmetry of a unit cell including lattice centering, the point group symmetry operations of reflection and improper rotation, the screw axis and glide plane symmetry operations; the combination of all these symmetry operations results in a total of 230 different space groups describing all possible crystal symmetries.
The elements of the space group fixing a point of space are the identity element, reflections and improper rotations. The translations form a normal abelian subgroup of rank 3, called the Bravais lattice. There are 14 possible types of Bravais lattice; the quotient of the space group by the Bravais lattice is a finite group, one of the 32 possible point groups. Translation is defined as the face moves from one point to another point. A glide plane is a reflection in a plane, followed by a translation parallel with that plane; this is noted depending on which axis the glide is along. There is the n glide, a glide along the half of a diagonal of a face, the d glide, a fourth of the way along either a face or space diagonal of the unit cell; the latter is called the diamond glide plane. In 17 space groups, due to the centering of the cell, the glides occur in two perpendicular directions i.e. the same glide plane can be called b or c, a or b, a or c. For example, group Abm2 could be called Acm2, group Ccca could be called Cccb.
In 1992, it was suggested to use symbol e for such planes. The symbols for five space groups have been modified: A screw axis is a rotation about an axis, followed by a translation along the direction of the axis; these are noted by a number, n, to describe the degree of rotation, where the number is how many operations must be applied to complete a full rotation. The degree of translation is added as a subscript showing how far along the axis the translation is, as a portion of the parallel lattice vector. So, 21 is a twofold rotation followed by a translation of 1/2 of the lattice vector; the general formula for the action of an element of a space group is y = M.x + D where M is its matrix, D is its vector, where the element transforms point x into point y. In general, D = D + D, where D is a unique function of M, zero for M being the identity; the matrices M form a point group, a basis of the space group. The lattice dimension can be less than the overall dimension, resulting in a "subperiodic" space group.
For:: One-dimensional line groups: Two-dimensional line groups: frieze groups: Wallpaper groups: Three-dimensional line groups. Some of these methods can assign several different names to the same space group, so altogether there are many thousands of different names. Number; the International Union of Crystallography publishes tables of all space group types, assigns each a unique number from 1 to 230. The numbering is arbitrary, except that groups with the same crystal system or point group are given consecutive numbers. International symbol or Hermann–Mauguin notation; the Hermann–Mauguin notation describes the lattice and some generators for the group. It has a shortened form called the international short symbol, the one most used in crystallography
In the field of mineralogy, fracture is the texture and shape of a rock's surface formed when a mineral is fractured. Minerals have a distinctive fracture, making it a principal feature used in their identification. Fracture differs from cleavage in that the latter involves clean splitting along the cleavage planes of the mineral's crystal structure, as opposed to more general breakage. All minerals exhibit fracture, but when strong cleavage is present, it can be difficult to see. Conchoidal fracture breakage that resembles the concentric ripples of a mussel shell, it occurs in amorphous or fine-grained minerals such as flint, opal or obsidian, but may occur in crystalline minerals such as quartz. Subconchoidal fracture is similar to with less significant curvature. Earthy fracture is reminiscent of freshly broken soil, it is seen in soft, loosely bound minerals, such as limonite and aluminite. Hackly fracture is jagged and not even, it occurs when metals are torn, so is encountered in native metals such as copper and silver.
Splintery fracture comprises sharp elongated points. It is seen in fibrous minerals such as chrysotile, but may occur in non-fibrous minerals such as kyanite. Uneven fracture is a rough one with random irregularities, it occurs in a wide range of minerals including arsenopyrite and magnetite. Rudolf Duda and Lubos Rejl: Minerals of the World http://www.galleries.com/minerals/property/fracture.htm
The streak of a mineral is the color of the powder produced when it is dragged across an un-weathered surface. Unlike the apparent color of a mineral, which for most minerals can vary the trail of finely ground powder has a more consistent characteristic color, is thus an important diagnostic tool in mineral identification. If no streak seems to be made, the mineral's streak is said to be colorless. Streak is important as a diagnostic for opaque and colored materials, it is less useful for silicate minerals, most of which have a white streak or are too hard to powder easily. The apparent color of a mineral can vary because of trace impurities or a disturbed macroscopic crystal structure. Small amounts of an impurity that absorbs a particular wavelength can radically change the wavelengths of light that are reflected by the specimen, thus change the apparent color. However, when the specimen is dragged to produce a streak, it is broken into randomly oriented microscopic crystals, small impurities do not affect the absorption of light.
The surface across which the mineral is dragged is called a "streak plate", is made of unglazed porcelain tile. In the absence of a streak plate, the unglazed underside of a porcelain bowl or vase or the back of a glazed tile will work. Sometimes a streak is more or described by comparing it with the "streak" made by another streak plate; because the trail left behind results from the mineral being crushed into powder, a streak can only be made of minerals softer than the streak plate, around 7 on the Mohs scale of mineral hardness. For harder minerals, the color of the powder can be determined by filing or crushing with a hammer a small sample, usually rubbed on a streak plate. Most minerals that are harder have an unhelpful white streak; some minerals leave a streak similar to their natural color, such as lazurite. Other minerals leave surprising colors, such as fluorite, which always has a white streak, although it can appear in purple, yellow, or green crystals. Hematite, black in appearance, leaves a red streak which accounts for its name, which comes from the Greek word "haima", meaning "blood."
Galena, which can be similar in appearance to hematite, is distinguished by its gray streak. Bishop, A. C.. R.. R.. Cambridge Guide to Minerals and Fossils. Cambridge: Cambridge University Press. Pp. 12–13. Holden, Martin; the Encyclopedia of Gemstones and Minerals. New York: Facts on File. p. 251. ISBN 1-56799-949-2. Schumann, Walter. Minerals of the World. New York: Sterling Publishing. Pp. 18–16. ISBN 0-00-219909-2. Physical Characteristics of Minerals, at Introduction to Mineralogy by Andrea Bangert What is Streak? from the Mineral Gallery