Mixed anion compounds, heteroanionic materials or mixed anion materials are

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one ele ...

s containing

cation An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

s and more than one kind of

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

. The compounds contain a single phase, rather than just a mixture.

Use in materials science

By having more than one anion, many more compounds can be made, and properties tuned to desirable values. In terms of optics, properties include laser damage threshold,

refractive index In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, o ...

birefringence Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. These optically anisotropic materials are said to be birefringent (or birefractive). The birefrin ...

absorption Absorption may refer to: Chemistry and biology *Absorption (biology), digestion **Absorption (small intestine) *Absorption (chemistry), diffusion of particles of gas or liquid into liquid or solid materials * Absorption (skin), a route by which ...

particularly in the

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiati ...

near infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

non-linearity In mathematics and science, a nonlinear system is a system in which the change of the output is not proportional to the change of the input. Nonlinear problems are of interest to engineers, biologists, physicists, mathematicians, and many other ...

. Mechanical properties can include ability to grow a large crystal, ability to form a thin layer, strength, or brittleness. Thermal properties can include

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends ...

thermal stability In thermodynamics, thermal stability describes the stability of a water body and its resistance to mixing.Schmidt, W. 1928. Über Temperatur und Stabilitätsverhältnisse von Seen. Geogr. Ann 10: 145 - 177. It is the amount of work needed to ...

, phase transition temperatures,

Thermal expansion coefficient Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kinetic ...

. For electrical properties, electric conductivity,

band gap In solid-state physics, a band gap, also called an energy gap, is an energy range in a solid where no electronic states can exist. In graphs of the electronic band structure of solids, the band gap generally refers to the energy difference ( ...

, superconducting transition temperature

piezoelectricity Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word ' ...

pyroelectricity Pyroelectricity (from the two Greek words ''pyr'' meaning fire, and electricity) is a property of certain crystals which are naturally electrically polarized and as a result contain large electric fields. Pyroelectricity can be described as the a ...

ferromagnetism Ferromagnetism is a property of certain materials (such as iron) which results in a large observed magnetic permeability, and in many cases a large magnetic coercivity allowing the material to form a permanent magnet. Ferromagnetic materials a ...

dielectric constant The relative permittivity (in older texts, dielectric constant) is the permittivity of a material expressed as a ratio with the electric permittivity of a vacuum. A dielectric is an insulating material, and the dielectric constant of an insulat ...

charge-density wave A charge density wave (CDW) is an ordered quantum fluid of electrons in a linear chain compound or layered crystal. The electrons within a CDW form a standing wave pattern and sometimes collectively carry an electric current. The electrons in such ...

transition can be adjusted.

Production

Many of the non-metals that could make mixed anion compounds may have greatly varying volatilities. This makes it more difficult to combine the elements together. Compounds may be produced in a solid state reaction, by heating solids together, either in a vacuum or a gas. Common gases used include, oxygen, hydrogen, ammonia, chlorine, fluorine, hydrogen sulfide, or carbon disulfide.

Soft chemical Soft chemistry (also known as chimie douce) is a type of chemistry that uses reactions at ambient temperature in open reaction vessels with reactions similar to those occurring in biological systems. Aims The aim of the soft chemistry is to synt ...

approaches to manufacture include

solvothermal synthesis Solvothermal synthesis is a method of producing chemical compounds, in which a solvent containing reagents is put under high pressure and temperature in an autoclave. Many substances dissolve better in the same solvent in such conditions than at st ...

, or substituting atoms in a structure by others, including by water, oxygen, fluorine or nitrogen. Teflon pouches can be used to separate different formulations. Thin film deposits can yield strained layers. High pressures can be used to prevent evaporation of volatiles. High pressure can result in different crystal forms, perhaps with higher coordination number.

Kinds

Elemental

* pnictochalcogenides **

oxypnictide In chemistry, oxypnictides are a class of materials composed of oxygen, a pnictogen (group-V, especially phosphorus and arsenic) and one or more other elements. Although this group of compounds has been recognized since 1995, interest in these com ...

s, including oxynitrides, oxyphosphides, oxyarsenides, oxyantimonides, and oxybismuthides * chalcohalides or chalcogenide halides ** oxyhalides, including

oxyfluoride In chemistry, molecular oxohalides (oxyhalides) are a group of chemical compounds in which both oxygen and halogen atoms are attached to another chemical element A in a single molecule. They have the general formula , where X = fluorine (F), chlor ...

oxychloride In chemistry, molecular oxohalides (oxyhalides) are a group of chemical compounds in which both oxygen and halogen atoms are attached to another chemical element A in a single molecule. They have the general formula , where X = fluorine (F), ...

oxybromide In chemistry, molecular oxohalides (oxyhalides) are a group of chemical compounds in which both oxygen and halogen atoms are attached to another chemical element A in a single molecule. They have the general formula , where X = fluorine (F), chlor ...

s, and

oxyiodide In chemistry, molecular oxohalides (oxyhalides) are a group of chemical compounds in which both oxygen and halogen atoms are attached to another chemical element A in a single molecule. They have the general formula , where X = fluorine (F), chlor ...

s ** fluorosulfides **

sulfide chloride Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds la ...

selenide chloride A selenide is a chemical compound containing a selenium anion with oxidation number of −2 (Se2−), much as sulfur does in a sulfide. The chemistry of the selenides and sulfides is similar. Similar to sulfide, in aqueous solution, the selenide i ...

s, and telluride chlorides **

sulfide bromide Sulfide ( British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds ...

s, selenide bromides, and

telluride bromide The telluride bromides are chemical compounds that contain both telluride ions (Te2−) and bromide ions (Br−). They are in the class of mixed anion compounds or chalcogenide halides : 220px, Cadmium sulfide, a prototypical metal chalcogenide, ...

s **

sulfide iodide Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds la ...

selenide iodide The selenide iodides are chemical compounds that contain both selenide ions (Se2−) and iodide ions (I−) and one or metal atoms. They are in the class of mixed anion compounds or chalcogenide halides : 220px, Cadmium sulfide, a prototypical me ...

s, and

telluride iodide The telluride iodides are chemical compounds that contain both telluride ions (Te2−) and iodide ions (I−). They are in the class of mixed anion compounds Mixed anion compounds, heteroanionic materials or mixed anion materials are chemical co ...

s * oxysulfides and

oxyselenides Oxyselenides are a group of chemical compounds that contain oxygen and selenium atoms (Figure 1). Oxyselenides can form a wide range of structures in compounds containing various transition metals, and thus can exhibit a wide range of properties. ...

oxyhydrides An oxyhydride is a mixed anion compound containing both oxide O2− and hydride ions H−. These compounds may be unexpected as the hydrogen and oxygen could be expected to react to form water. But if the metals making up the cations are electropos ...

* halopnictides ** fluoropnictides, including fluorophosphides, fluoroarsenides, fluoroantimonides, and fluorobismuthides

Molecular anions

* borohydride-chloride * disulfide dithioorthovanadate

Oxyanions

* halocarbonates, including

carbonate fluoride A carbonate fluoride, fluoride carbonate, fluorocarbonate or fluocarbonate is a double salt containing both carbonate and fluoride. The salts are usually insoluble in water, and can have more than one kind of metal cation to make more complex comp ...

carbonate chloride The carbonate chlorides are double salts containing both carbonate and chloride anions. Quite a few minerals are known. Several artificial compounds have been made. Some complexes have both carbonate and chloride ligands. They are part of the fam ...

s, and

carbonate bromide A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonat ...

s * phosphates, including

fluoride phosphate The fluoride phosphates or phosphate fluorides are inorganic double salts that contain both fluoride and phosphate anions. In mineralogy, Hey's Chemical Index of Minerals groups these as 22.1. The Nickel–Strunz classification, Nickel-Strunz grou ...

chloride phosphate The chloride ion is the anion (negatively charged ion) Cl−. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride salts ...

phosphate molybdates In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...

, and

phosphate arsenates In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...

* borates **

halide borates In chemistry, a halide (rarely halogenide) is a binary chemical compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative (or more electropositive) than the halogen, to make a flu ...

, including

fluoride borate The borate fluorides or fluoroborates are compounds containing borate or complex borate ions along with fluoride ions that form salts with cations such as metals. They are in the broader category of mixed anion compounds. They are not to be confuse ...

borate chloride The borate chlorides are chemical compounds that contain both borate ions and chloride ions. They are mixed anion compounds. Many of them are minerals. Those minerals that crystallise with water (hydrates) may be found in evaporite An evaporite ...

borate bromide The borate bromides are mixed anion compounds that contain borate and bromide anions. They are in the borate halide family of compounds which also includes borate fluorides, borate chlorides, and borate iodide The borate iodides are mixed anion ...

s and

borate iodide The borate iodides are mixed anion compounds that contain both borate and iodide anions. They are in the borate halide family of compounds which also includes borate fluorides, borate chloride The borate chlorides are chemical compounds that con ...

s **

chalcogenide borate : 220px, Cadmium sulfide, a prototypical metal chalcogenide, is used as a yellow pigment. A chalcogenide is a chemical compound consisting of at least one chalcogen anion and at least one more electropositive element. Although all group 16 elemen ...

s, including

sulfide borate Borate sulfides are chemical mixed anion compounds that contain any kind of borate and sulfide Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− io ...

s ** borate carbonates, borate nitrates,

borate sulfate Borate sulfates are mixed anion compounds containing separate borate and sulfate anions. They are distinct from the borosulfates The borosulfates are heteropoly anion compounds which have sulfate groups attached to boron atoms. Other possible ter ...

s, borate phosphates **

borate acetate A borate is any of several boron oxyanions, negative ions consisting of boron and oxygen, such as orthoborate , metaborate , or tetraborate ; or any salt with such anions, such as sodium metaborate, and disodium tetraborate . The name also r ...

s ** Condensed borates:

borosulfate The borosulfates are heteropoly anion compounds which have sulfate groups attached to boron atoms. Other possible terms are sulfatoborates or boron-sulfur oxides. The ratio of sulfate to borate reflects the degree of condensation. With (SO4)4sup ...

boroselenate The boroselenates are chemical compounds containing interlinked borate and selenate The selenate ion is . Selenates are analogous to sulfates and have similar chemistry. They are highly soluble in aqueous solutions at ambient temperatures. Un ...

borotellurate The borotellurates are heteropoly anion compounds which have tellurate groups attached to boron atoms. The ratio of tellurate to borate reflects the degree of condensation. In eO4(BO3)2sup>8- the anions are linked into a chain. In eO2(BO3)4sup>10 ...

boroantimonate Boroantimonates are chemical compounds in which borate and antimonate In chemistry an antimonate is a compound which contains a metallic element, oxygen, and antimony in an oxidation state of +5. These compounds adopt polymeric structures with M-O- ...

borophosphate The borophosphates are mixed anion compounds containing borate and phosphate anions, which may be joined together by a common oxygen atom. Compounds that contain water or hydroxy groups can also be included in the class of compounds. Borophosphate ...

boroselenite The boroselenites are heteropoly anion chemical compounds containing selenite and borate groups linked by common oxygen atoms. They are not to be confused with the boroselenates with have a higher oxidation state for selenium, and extra oxygen ...

s * sulfates **

sulfate fluoride The sulfate fluorides are double salts that contain both sulfate and fluoride anions. They are in the class of mixed anion compounds. Some of these minerals are deposited in fumaroles. Fluoride sulfates were first discovered by Jean Charles de Ma ...

s and

sulfate chloride The sulfate chlorides are double salts containing both sulfate (SO42–) and chloride (Cl–) anions. They are distinct from the chlorosulfates, which have a chlorine atom attached to the sulfur as the ClSO3− anion. Many minerals in this famil ...

s **

sulfate arsenate The sulfate or sulphate ion is a polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many ...

selenite fluorides A selenite fluoride is a chemical compound or salt that contains fluoride and Selenite (ion), selenite anions ( and ). These are mixed anion compounds. Some have third anions, including nitrate (), molybdate (), oxalate (), selenate (), silicate () ...

iodate fluoride The iodate fluorides are chemical compounds which contain both iodate and fluoride anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is ...

s, * Silicates ** sulfide silicates

Fluoroanions

Mixed valency and oligomers

Some elements can form several different kinds of anions, and compounds may exist with more than one. Examples include the iodate periodates,

sulfite sulfate A sulfite sulfate is a chemical compound that contains both sulfite and sulfate anions O3sup>2− O4sup>2−. These compounds were discovered in the 1980s as calcium and rare earth element salts. Minerals in this class were later discovered. Mine ...

s and

selenite selenate A selenate selenite is a chemical compound or salt that contains selenite and selenate anions (SeO32- and SeO42-). These are mixed anion compounds Mixed anion compounds, heteroanionic materials or mixed anion materials are chemical compounds con ...

s. These kinds also include different oligomeric forms such as phosphates or fluorotitanates, such as i₄F₂₀sup>4- and iF₅sup>−.

Organic

oxalate formate Oxalate (IUPAC: ethanedioate) is an anion with the formula C2O42−. This dianion is colorless. It occurs naturally, including in some foods. It forms a variety of salts, for example sodium oxalate (Na2C2O4), and several esters such as dimethyl ...

References

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