Aluminium sulfate is a chemical compound with the formula Al23. It is soluble in water and is used as a coagulating agent in the purification of drinking water and waste water treatment plants, in paper manufacturing; the anhydrous form occurs as a rare mineral millosevichite, found e.g. in volcanic environments and on burning coal-mining waste dumps. Aluminium sulfate is if encountered as the anhydrous salt, it forms a number of different hydrates, of which the hexadecahydrate Al23•16H2O and octadecahydrate Al23•18H2O are the most common. The heptadecahydrate, whose formula can be written as 23•5H2O, occurs as the mineral alunogen. Aluminium sulfate is sometimes called papermaker's alum in certain industries. However, the name "alum" is more and properly used for any double sulfate salt with the generic formula XAl2·12H2O, where X is a monovalent cation such as potassium or ammonium. Aluminium sulfate may be made by adding aluminium hydroxide, Al3, to sulfuric acid, H2SO4: 2 Al3 + 3 H2SO4 → Al23 + 6H2Oor by heating aluminum metal in a sulfuric acid solution: 2 Al + 3 H2SO4 → Al23 + 3 H2↑ The alum schists employed in the manufacture of aluminium sulfate are mixtures of iron pyrite, aluminium silicate and various bituminous substances, are found in upper Bavaria, Bohemia and Scotland.
These are either exposed to the weathering action of the air. In the roasting process, sulfuric acid is formed and acts on the clay to form aluminium sulfate, a similar condition of affairs being produced during weathering; the mass is now systematically extracted with water, a solution of aluminium sulfate of specific gravity 1.16 is prepared. This solution is allowed to stand for some time, is evaporated until ferrous sulfate crystallizes on cooling, it is now allowed to stand for some time, decanted from any sediment. In the preparation of aluminum sulfate from clays or from bauxite, the material is calcined mixed with sulfuric acid and heated to boiling; when cryolite is used as the ore, it is mixed with calcium heated. By this means, sodium aluminate is formed; the precipitate is dissolved in sulfuric acid. It is sometimes used in the human food industry as a firming agent for food starch, where it takes on E number E520, in animal feed as a bactericide. Aluminum sulfate may be used as a deodorant, an astringent, or as a stiptic for superficial shaving wounds.
It improves vaccine immunogenicity as a vaccine adjuvant "by facilitating the slow release of antigen from the vaccine depot formed at the site of inoculation."Aluminium sulfate is used in water purification and as a mordant in dyeing and printing textiles. In water purification, it causes suspended impurities to coagulate into larger particles and settle to the bottom of the container more easily; this process is called flocculation. Research suggests that in Australia, aluminium sulfate used this way in drinking water treatment is the primary source of hydrogen sulfide gas in sanitary sewer systems. An improper and excess application incident in 1988 polluted the water supply of Camelford in Cornwall; when dissolved in a large amount of neutral or alkaline water, aluminium sulfate produces a gelatinous precipitate of aluminium hydroxide, Al3. In dyeing and printing cloth, the gelatinous precipitate helps the dye adhere to the clothing fibers by rendering the pigment insoluble. Aluminium sulfate is sometimes used to reduce the pH of garden soil, as it hydrolyzes to form the aluminium hydroxide precipitate and a dilute sulfuric acid solution.
An example of what changing the pH level of soil can do to plants is visible when looking at Hydrangea macrophylla. The gardener can add aluminium sulfate to the soil to reduce the pH which in turn will result in the flowers of the Hydrangea turning a different color; the aluminium is. In the construction industry, it is used as waterproofing accelerator in concrete. Another use is a foaming agent in fire fighting foam. In limnology, Alum is effectively employed to control levels of soluble ortho-phosphate and to agglomerate suspended dirt particles for improved clarification; the product can be applied as a granular product or as "Liquid Alum", water + dissolved ALum. pH must be monitored in lakes with valuable fish when considering an Alum treatment. Alum is quite acidic and a lake with low pH or a lake lacking a natural carbonate buffering capacity may find that the pH falls below 6 and to level when fish as harmed or killed. In such cases, a buffering agent - such as lime or Soda Ash or Sodium Bicarbonate - may be applied with the Alum to prevent a precipitous drop in pH.
It can be effective as a molluscicide, killing spanish slugs. Mordants aluminium triacetate and aluminium sulfacetate can be prepared from aluminium sulfate, the product formed being determined by the amount of lead acetate used: Al23 + 3 Pb2 → 2 Al3 + 3 PbSO4Al23 + 2 Pb2 → Al2SO44 + 2 PbSO4 The compound decomposes to γ−alumina and sulfur trioxide when heated between 580 and 900 °C, it combines wi
Aluminium bromide is any chemical compound with the empirical formula AlBrx. Aluminium tribromide is the most common form of aluminium bromide, it is sublimable hygroscopic solid. The dimeric form of aluminium tribromide predominates in the solid state, in solutions in noncoordinating solvents, in the melt, in the gas phase. Only at high temperatures do these dimers break up into monomers: Al2Br6 → 2 AlBr3 ΔH°diss = 59 kJ/molThe species aluminium monobromide forms from the reaction of HBr with Al metal at high temperature, it disproportionates near room temperature: 6/n "n" → Al2Br6 + 4 AlThis reaction is reversed at temperatures higher than 1000 °C. Aluminium monobromide has been crystallographically characterized in the form the tetrameric adduct Al4Br44; this species is electronically related to cyclobutane. Theory suggest that the diatomic aluminium monobromide condenses to a dimer and a tetrahedral cluster Al4Br4, akin to the analogous boron compound. Al2Br6 consists of two AlBr4 tetrahedra.
The molecular symmetry is D2h. The monomer AlBr3, observed only in the vapor, can be described as D3h point group; the atomic hybridization of aluminium is described as sp2. The Br-Al-Br bond angles are 120 °. By far the most common form of aluminium bromide is Al2Br6; this species exists as hygroscopic colorless solid at standard conditions. Typical impure samples are yellowish or red-brown due to the presence of iron-containing impurities, it is prepared by the reaction of HBr with Al: 2 Al + 6 HBr → Al2Br6 + 3 H2Alternatively, the direct bromination occurs also: 2 Al + 3 Br2 → Al2Br6 Al2Br6 dissociates to give the strong Lewis acid, AlBr3. Regarding the tendency of Al2Br6 to dimerize, it is common for heavier main group halides to exist as aggregates larger than implied by their empirical formulae. Lighter main group halides such as boron tribromide do not show this tendency, in part due to the smaller size of the central atom. Consistent with its Lewis acidic character, water hydrolizes Al2Br6 with evolution of HBr and formation of Al-OH-Br species.
It reacts with alcohols and carboxylic acids, although less vigorously than with water. With simple Lewis bases, Al2Br6 forms adducts, such as AlBr3L. Aluminium tribromide reacts with carbon tetrachloride at 100 °C to form carbon tetrabromide: 4 AlBr3 + 3 CCl4 → 4 AlCl3 + 3 CBr4and with phosgene yields carbonyl bromide and aluminium chlorobromide: AlBr3 + COCl2 → COBr2 + AlCl2BrAl2Br6 is used as a catalyst for the Friedel-Crafts alkylation reaction. Related Lewis acid-promoted reactions include as epoxide ring openings and decomplexation of dienes from iron carbonyls, it is a stronger Lewis acid than the more common Al2Cl6. Aluminium tribromide is a reactive material
A chemical compound is a chemical substance composed of many identical molecules composed of atoms from more than one element held together by chemical bonds. A chemical element bonded to an identical chemical element is not a chemical compound since only one element, not two different elements, is involved. There are four types of compounds, depending on how the constituent atoms are held together: molecules held together by covalent bonds ionic compounds held together by ionic bonds intermetallic compounds held together by metallic bonds certain complexes held together by coordinate covalent bonds. A chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using the standard abbreviations for the chemical elements, subscripts to indicate the number of atoms involved. For example, water is composed of two hydrogen atoms bonded to one oxygen atom: the chemical formula is H2O. Many chemical compounds have a unique numerical identifier assigned by the Chemical Abstracts Service: its CAS number.
A compound can be converted to a different chemical composition by interaction with a second chemical compound via a chemical reaction. In this process, bonds between atoms are broken in both of the interacting compounds, bonds are reformed so that new associations are made between atoms. Any substance consisting of two or more different types of atoms in a fixed stoichiometric proportion can be termed a chemical compound, it follows from their being composed of fixed proportions of two or more types of atoms that chemical compounds can be converted, via chemical reaction, into compounds or substances each having fewer atoms. The ratio of each element in the compound is expressed in a ratio in its chemical formula. A chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using the standard abbreviations for the chemical elements, subscripts to indicate the number of atoms involved. For example, water is composed of two hydrogen atoms bonded to one oxygen atom: the chemical formula is H2O.
In the case of non-stoichiometric compounds, the proportions may be reproducible with regard to their preparation, give fixed proportions of their component elements, but proportions that are not integral. Chemical compounds have a unique and defined chemical structure held together in a defined spatial arrangement by chemical bonds. Chemical compounds can be molecular compounds held together by covalent bonds, salts held together by ionic bonds, intermetallic compounds held together by metallic bonds, or the subset of chemical complexes that are held together by coordinate covalent bonds. Pure chemical elements are not considered chemical compounds, failing the two or more atom requirement, though they consist of molecules composed of multiple atoms. Many chemical compounds have a unique numerical identifier assigned by the Chemical Abstracts Service: its CAS number. There is varying and sometimes inconsistent nomenclature differentiating substances, which include non-stoichiometric examples, from chemical compounds, which require the fixed ratios.
Many solid chemical substances—for example many silicate minerals—are chemical substances, but do not have simple formulae reflecting chemically bonding of elements to one another in fixed ratios. It may be argued that they are related to, rather than being chemical compounds, insofar as the variability in their compositions is due to either the presence of foreign elements trapped within the crystal structure of an otherwise known true chemical compound, or due to perturbations in structure relative to the known compound that arise because of an excess of deficit of the constituent elements at places in its structure. Other compounds regarded as chemically identical may have varying amounts of heavy or light isotopes of the constituent elements, which changes the ratio of elements by mass slightly. Compounds are held together through a variety of different types of bonding and forces; the differences in the types of bonds in compounds differ based on the types of elements present in the compound.
London dispersion forces are the weakest force of all intermolecular forces. They are temporary attractive forces that form when the electrons in two adjacent atoms are positioned so that they create a temporary dipole. Additionally, London dispersion forces are responsible for condensing non polar substances to liquids, to further freeze to a solid state dependent on how low the temperature of the environment is. A covalent bond known as a molecular bond, involves the sharing of electrons between two atoms; this type of bond occurs between elements that fall close to each other on the periodic table of elements, yet it is observed between some metals and nonmetals. This is due to the mechanism of this type of bond. Elements that fall close to each other on the periodic table tend to have similar electronegativities, which means they have a similar affinity for electrons. Since neither element has a stronger affinity to donate or gain electrons, it causes the elements to share electrons so both elements have a more stable octet.
Ionic bonding occurs when valence electrons are transferred between elements. Opposite to covalent bonding, this chemical bond creates two oppositely charged ions; the metals in ionic bonding
Simplified molecular-input line-entry system
The simplified molecular-input line-entry system is a specification in the form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules; the original SMILES specification was initiated in the 1980s. It has since been extended. In 2007, an open standard called. Other linear notations include the Wiswesser line notation, ROSDAL, SYBYL Line Notation; the original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. Acknowledged for their parts in the early development were "Gilman Veith and Rose Russo and Albert Leo and Corwin Hansch for supporting the work, Arthur Weininger and Jeremy Scofield for assistance in programming the system." The Environmental Protection Agency funded the initial project to develop SMILES. It has since been modified and extended by others, most notably by Daylight Chemical Information Systems.
In 2007, an open standard called "OpenSMILES" was developed by the Blue Obelisk open-source chemistry community. Other'linear' notations include the Wiswesser Line Notation, ROSDAL and SLN. In July 2006, the IUPAC introduced the InChI as a standard for formula representation. SMILES is considered to have the advantage of being more human-readable than InChI; the term SMILES refers to a line notation for encoding molecular structures and specific instances should be called SMILES strings. However, the term SMILES is commonly used to refer to both a single SMILES string and a number of SMILES strings; the terms "canonical" and "isomeric" can lead to some confusion when applied to SMILES. The terms are not mutually exclusive. A number of valid SMILES strings can be written for a molecule. For example, CCO, OCC and CC all specify the structure of ethanol. Algorithms have been developed to generate the same SMILES string for a given molecule; this SMILES is unique for each structure, although dependent on the canonicalization algorithm used to generate it, is termed the canonical SMILES.
These algorithms first convert the SMILES to an internal representation of the molecular structure. Various algorithms for generating canonical SMILES have been developed and include those by Daylight Chemical Information Systems, OpenEye Scientific Software, MEDIT, Chemical Computing Group, MolSoft LLC, the Chemistry Development Kit. A common application of canonical SMILES is indexing and ensuring uniqueness of molecules in a database; the original paper that described the CANGEN algorithm claimed to generate unique SMILES strings for graphs representing molecules, but the algorithm fails for a number of simple cases and cannot be considered a correct method for representing a graph canonically. There is no systematic comparison across commercial software to test if such flaws exist in those packages. SMILES notation allows the specification of configuration at tetrahedral centers, double bond geometry; these are structural features that cannot be specified by connectivity alone and SMILES which encode this information are termed isomeric SMILES.
A notable feature of these rules is. The term isomeric SMILES is applied to SMILES in which isotopes are specified. In terms of a graph-based computational procedure, SMILES is a string obtained by printing the symbol nodes encountered in a depth-first tree traversal of a chemical graph; the chemical graph is first trimmed to remove hydrogen atoms and cycles are broken to turn it into a spanning tree. Where cycles have been broken, numeric suffix labels are included to indicate the connected nodes. Parentheses are used to indicate points of branching on the tree; the resultant SMILES form depends on the choices: of the bonds chosen to break cycles, of the starting atom used for the depth-first traversal, of the order in which branches are listed when encountered. Atoms are represented by the standard abbreviation of the chemical elements, in square brackets, such as for gold. Brackets may be omitted in the common case of atoms which: are in the "organic subset" of B, C, N, O, P, S, F, Cl, Br, or I, have no formal charge, have the number of hydrogens attached implied by the SMILES valence model, are the normal isotopes, are not chiral centers.
All other elements must be enclosed in brackets, have charges and hydrogens shown explicitly. For instance, the SMILES for water may be written as either O or. Hydrogen may be written as a separate atom; when brackets are used, the symbol H is added if the atom in brackets is bonded to one or more hydrogen, followed by the number of hydrogen atoms if greater than 1 by the sign + for a positive charge or by - for a negative charge. For example, for ammonium. If there is more than one charge, it is written as digit.
Aluminium oxide or aluminum oxide is a chemical compound of aluminium and oxygen with the chemical formula Al2O3. It is the most occurring of several aluminium oxides, identified as aluminium oxide, it is called alumina and may be called aloxide, aloxite, or alundum depending on particular forms or applications. It occurs in its crystalline polymorphic phase α-Al2O3 as the mineral corundum, varieties of which form the precious gemstones ruby and sapphire. Al2O3 is significant in its use to produce aluminium metal, as an abrasive owing to its hardness, as a refractory material owing to its high melting point. Corundum is the most common occurring crystalline form of aluminium oxide. Rubies and sapphires are gem-quality forms of corundum, which owe their characteristic colors to trace impurities. Rubies are given their characteristic deep red color and their laser qualities by traces of chromium. Sapphires come in different colors given by various other impurities, such as titanium. Al2O3 is an electrical insulator but has a high thermal conductivity for a ceramic material.
Aluminium oxide is insoluble in water. In its most occurring crystalline form, called corundum or α-aluminium oxide, its hardness makes it suitable for use as an abrasive and as a component in cutting tools. Aluminium oxide is responsible for the resistance of metallic aluminium to weathering. Metallic aluminium is reactive with atmospheric oxygen, a thin passivation layer of aluminium oxide forms on any exposed aluminium surface; this layer protects the metal from further oxidation. The thickness and properties of this oxide layer can be enhanced using a process called anodising. A number of alloys, such as aluminium bronzes, exploit this property by including a proportion of aluminium in the alloy to enhance corrosion resistance; the aluminium oxide generated by anodising is amorphous, but discharge assisted oxidation processes such as plasma electrolytic oxidation result in a significant proportion of crystalline aluminium oxide in the coating, enhancing its hardness. Aluminium oxide was taken off the United States Environmental Protection Agency's chemicals lists in 1988.
Aluminium oxide is on the EPA's Toxics Release Inventory list. Aluminium oxide is an amphoteric substance, meaning it can react with both acids and bases, such as hydrofluoric acid and sodium hydroxide, acting as an acid with a base and a base with an acid, neutralising the other and producing a salt. Al2O3 + 6 HF → 2 AlF3 + 3 H2O Al2O3 + 2 NaOH + 3 H2O → 2 NaAl4 The most common form of crystalline aluminium oxide is known as corundum, the thermodynamically stable form; the oxygen ions form a nearly hexagonal close-packed structure with the aluminium ions filling two-thirds of the octahedral interstices. Each Al3+ center is octahedral. In terms of its crystallography, corundum adopts a trigonal Bravais lattice with a space group of R3c; the primitive cell contains two formula units of aluminium oxide. Aluminium oxide exists in other, phases, including the cubic γ and η phases, the monoclinic θ phase, the hexagonal χ phase, the orthorhombic κ phase and the δ phase that can be tetragonal or orthorhombic.
Each has properties. Cubic γ-Al2O3 has important technical applications; the so-called β-Al2O3 proved to be NaAl11O17. Molten aluminium oxide near the melting temperature is 2/3 tetrahedral, 1/3 5-coordinated, with little octahedral Al-O present. Around 80% of the oxygen atoms are shared among three or more Al-O polyhedra, the majority of inter-polyhedral connections are corner-sharing, with the remaining 10–20% being edge-sharing; the breakdown of octahedra upon melting is accompanied by a large volume increase, the density of the liquid close to its melting point is 2.93 g/cm3. The structure of molten alumina is temperature dependent and the fraction of 5- and 6-fold aluminium increases during cooling, at the expense of tetrahedral AlO4 units, approaching the local structural arrangements found in amorphous alumina. Aluminium hydroxide minerals are the main component of the principal ore of aluminium. A mixture of the minerals comprise bauxite ore, including gibbsite and diaspore, along with impurities of iron oxides and hydroxides and clay minerals.
Bauxites are found in laterites. Bauxite is purified by the Bayer process: Al2O3 + H2O + NaOH → NaAl4 Al3 + NaOH → NaAl4Except for SiO2, the other components of bauxite do not dissolve in base. Upon filtering the basic mixture, Fe2O3 is removed; when the Bayer liquor is cooled, Al3 precipitates. NaAl4 → NaOH + Al3The solid Al3 Gibbsite is calcined to give aluminium oxide: 2 Al3 → Al2O3 + 3 H2OThe product aluminium oxide tends to be multi-phase, i.e. consisting of several phases of aluminium oxide rather than corundum. The production process can therefore be optimized to produce a tailored product; the type of phases present affects, for example, the solubility and pore structure of the aluminium oxide product which, in turn, affects the cost of aluminium production and pollution control. Known as alundum or aloxite in the mining and materials science communities, aluminium oxide finds wide use. Annual world production of aluminium oxide in 2015 was 115 million tonnes, over 90% of, used in the manufacture of aluminium metal.
The major uses of speciali
Aluminium nitrate is a white, water-soluble salt of aluminium and nitric acid, most existing as the crystalline hydrate, aluminium nitrate nonahydrate, Al3·9H2O. Aluminium nitrate cannot be synthesized by the reaction of aluminium with concentrated nitric acid, as the aluminium forms a passivation layer. Aluminium nitrate may instead be prepared by the reaction of nitric acid with aluminium chloride. Nitrosyl chloride is produced as a by-product. More conveniently, the salt can be made by reacting nitric acid with aluminium hydroxide. Aluminium nitrate may be prepared a metathesis reaction between aluminium sulfate and a nitrate salt with a suitable cation such as barium, calcium, silver, or lead. E.g. Al23 + 3Ba2 → 2Al3 + 3BaSO4 Aluminium nitrate is a strong oxidizing agent, it is used in tanning leather, corrosion inhibitors, extraction of uranium, petroleum refining, as a nitrating agent. The nonahydrate and other hydrated aluminium nitrates have many applications; these salts are used to produce alumina for preparation of insulating papers, in cathode ray tube heating elements, on transformer core laminates.
The hydrated salts are used for the extraction of actinide elements. It is used in the laboratory and classroom such as in the reaction: Al3 + 3 NaOH → Al3 + 3 NaNO3It is, much less encountered aluminium chloride and aluminium sulphate. MSDS of nonahydrate Government of Canada Fact Sheets and Frequently Asked Questions: Aluminum Salts
Aluminium or aluminum is a chemical element with symbol Al and atomic number 13. It is a silvery-white, soft and ductile metal in the boron group. By mass, aluminium makes up about 8% of the Earth's crust; the chief ore of aluminium is bauxite. Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is found combined in over 270 different minerals. Aluminium is remarkable for its low density and its ability to resist corrosion through the phenomenon of passivation. Aluminium and its alloys are vital to the aerospace industry and important in transportation and building industries, such as building facades and window frames; the oxides and sulfates are the most useful compounds of aluminium. Despite its prevalence in the environment, no known form of life uses aluminium salts metabolically, but aluminium is well tolerated by plants and animals; because of these salts' abundance, the potential for a biological role for them is of continuing interest, studies continue.
Of aluminium isotopes, only 27Al is stable. This is consistent with aluminium having an odd atomic number, it is the only aluminium isotope that has existed on Earth in its current form since the creation of the planet. Nearly all the element on Earth is present as this isotope, which makes aluminium a mononuclidic element and means that its standard atomic weight equates to that of the isotope; the standard atomic weight of aluminium is low in comparison with many other metals, which has consequences for the element's properties. All other isotopes of aluminium are radioactive; the most stable of these is 26Al and therefore could not have survived since the formation of the planet. However, 26Al is produced from argon in the atmosphere by spallation caused by cosmic ray protons; the ratio of 26Al to 10Be has been used for radiodating of geological processes over 105 to 106 year time scales, in particular transport, sediment storage, burial times, erosion. Most meteorite scientists believe that the energy released by the decay of 26Al was responsible for the melting and differentiation of some asteroids after their formation 4.55 billion years ago.
The remaining isotopes of aluminium, with mass numbers ranging from 21 to 43, all have half-lives well under an hour. Three metastable states are known, all with half-lives under a minute. An aluminium atom has 13 electrons, arranged in an electron configuration of 3s23p1, with three electrons beyond a stable noble gas configuration. Accordingly, the combined first three ionization energies of aluminium are far lower than the fourth ionization energy alone. Aluminium can easily surrender its three outermost electrons in many chemical reactions; the electronegativity of aluminium is 1.61. A free aluminium atom has a radius of 143 pm. With the three outermost electrons removed, the radius shrinks to 39 pm for a 4-coordinated atom or 53.5 pm for a 6-coordinated atom. At standard temperature and pressure, aluminium atoms form a face-centered cubic crystal system bound by metallic bonding provided by atoms' outermost electrons; this crystal system is shared by some other metals, such as copper. Aluminium metal, when in quantity, is shiny and resembles silver because it preferentially absorbs far ultraviolet radiation while reflecting all visible light so it does not impart any color to reflected light, unlike the reflectance spectra of copper and gold.
Another important characteristic of aluminium is its low density, 2.70 g/cm3. Aluminium is a soft, lightweight and malleable with appearance ranging from silvery to dull gray, depending on the surface roughness, it is nonmagnetic and does not ignite. A fresh film of aluminium serves as a good reflector of visible light and an excellent reflector of medium and far infrared radiation; the yield strength of pure aluminium is 7–11 MPa, while aluminium alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminium has stiffness of steel, it is machined, cast and extruded. Aluminium atoms are arranged in a face-centered cubic structure. Aluminium has a stacking-fault energy of 200 mJ/m2. Aluminium is a good thermal and electrical conductor, having 59% the conductivity of copper, both thermal and electrical, while having only 30% of copper's density. Aluminium is capable of superconductivity, with a superconducting critical temperature of 1.2 kelvin and a critical magnetic field of about 100 gauss.
Aluminium is the most common material for the fabrication of superconducting qubits. Aluminium's corrosion resistance can be excellent due to a thin surface layer of aluminium oxide that forms when the bare metal is exposed to air preventing further oxidation, in a process termed passivation; the strongest aluminium alloys are less corrosion resistant due to galvanic reactions with alloyed copper. This corrosion resistance is reduced by aqueous salts in the presence of dissimilar metals. In acidic solutions, aluminium reacts with water to form hydrogen, in alkaline ones to form aluminates—protective passivation under these conditions is negligible; because it is corroded by dissolved chlorides, such as common sodium chloride, household plumbing is never made from aluminium. However, because