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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 containing cations and more than one kind of anion. The compounds contain a single phase, rather than just a mixture. Use in materials science By havin .... Some have third anions. Naming A selenate selenite compound may also be called a selenite selenate. Production One way to produce a selenate selenite compound is to evaporate a water solution of selenate and selenite compounds. Properties On heating, selenate selenites lose SeO2 and O2 and yield selenites, and ultimately metal oxides. Related Related to these are the sulfate sulfites and tellurate tellurites. They can be classed as mixed valent compounds. List References {{Selenites Selenates Selenites Mixed anion compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenite (ion)
Selenite refers to the anion with the chemical formula . It is the oxyanion of selenium. It is the selenium analog of the sulfite ion, . Thus selenite is pyramidal and selenium is assigned oxidation state +4. Selenite also refers to compounds that contains this ion, for example sodium selenite which is a common source of selenite. Selenite also refers to the esters of selenous acid, for example dimethyl selenite . Synthesis and reactions Selenite salts can be prepared by neutralizing solutions of selenous acid, which is generated by dissolving selenium dioxide in water. The process proceeds via the hydrogenselenite ion, . Selenite reacts with elemental sulfur to form thioselenate: : Most selenite salts can be formed by heating the metal oxide with selenium dioxide Selenium dioxide is the chemical compound with the formula SeO2. This colorless solid is one of the most frequently encountered compounds of selenium. Properties Solid SeO2 is a one-dimensional polymer, the chain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenate
The selenate ion is . Selenates are analogous to sulfates and have similar chemistry. They are highly soluble in aqueous solutions at ambient temperatures. Unlike sulfate, selenate is a somewhat good oxidizer; it can be reduced to selenite or selenium. In strongly acidic conditions, the hydrogen selenate ion, , is formed. It corresponds to the selenic acid, H2SeO4, which is a strong acid and can in its concentrated form dissolve gold. The element selenium exhibits several valence states. Selenate is the least reduced, followed by selenite, and elemental selenium; selenide is even more reduced than elemental selenium. The valence state is an important factor to the toxicity of selenium. Selenate is the form required by organisms that need selenium as a micronutrient. These organisms have the ability to acquire, metabolize and excrete selenium. The level at which selenium becomes toxic varies from species to species and is related to other environmental factors like pH a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons while an anion is a negatively charged ion with more electrons than protons. Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomic ions. In the case of physical ionization in a fluid (gas or liquid), "ion pairs" are created by spontaneous molecule collisions, where each generated pair consists of a free electron and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mixed Anion Compounds
Mixed anion compounds, heteroanionic materials or mixed anion materials are chemical compounds containing cations and more than one kind of anion. 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, birefringence, absorption particularly in the ultraviolet or near infrared, non-linearity. 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, thermal stability, phase transition temperatures, Thermal expansion coefficient. For electrical properties, electric conductivity, band gap, superconducting transition temperature piezoelectricity, pyroelectricity, ferromagnetism, dielectric constant, charge-density wave transition can be adjusted. Pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfate Sulfite
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. Minerals may have sulfite as an essential component, or have it substituted for another anion as in alloriite. The related ions 3SOSO2sup>2− and O2SO)2SO2sup>2− may be produced in a reaction between sulfur dioxide and sulfate and exist in the solid form as tetramethyl ammonium salts. They have a significant partial pressure of sulfur dioxide. Related compounds are selenate selenites and tellurate tellurites with a varying chalcogen. They can be classed as mixed valent compounds. Production Europium and cerium rare earth sulfite sulfates are produced when heating the metal sulfite trihydrate in air. Ce2(SO3)3.3H2O + O2 → Ce2(SO3)2SO4 + 3H2O Ce2(SO3)3.3H2O + O2 → Ce2SO3(SO4)2 + 3H2O Other rare earth sulfite sulfates can be cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tellurate Tellurite
A tellurite tellurate is chemical compound or salt that contains tellurite and tellurate anions eO3sup>2- eO4 sup>2-. These are mixed anion compounds, meaning the compounds are cations that contain one or more anions. Some have third anions. Environmentally, tellurite eO3sup>2- is the more abundant anion due to tellurate's eO4 sup>2- low solubility limiting its concentration in biospheric waters. Another way to refer to the anions is tellurium's oxyanions, which happen to be relatively stable. Naming A tellurite tellurate compound may also be called a tellurate tellurite. Compounds that contain the anions follow basic nomenclature rules, the cation is named first, followed by the anion. As individual ions current IUPAC naming conventions dictate that compounds containing what was conventionally known as the tellurite ion, eO3sup>2-, be named as tellurate (IV) compounds, while other tellurates are labeled tellurate (VI) compounds. Furthering confusion, a number of other tellu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Weight
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and biochemistry, the distinction from ions is dropped and ''molecule'' is often used when referring to polyatomic ions. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (two hydrogen atoms and one oxygen atom; H2O). In the kinetic theory of gases, the term ''molecule'' is often used for any gaseous particle regardless of its composition. This relaxes the requirement that a molecule contains two or more atoms, since the noble gases are individual atoms. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are typically not consi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Group
In mathematics, physics and chemistry, a space group is the symmetry group of an object in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of an object that leave it unchanged. In three dimensions, space groups are classified into 219 distinct types, or 230 types if chiral copies are considered distinct. Space groups are discrete cocompact groups of isometries of an oriented Euclidean space in any number of dimensions. In dimensions other than 3, they are sometimes called Bieberbach groups. In crystallography, space groups are also called the crystallographic or Fedorov groups, and represent a description of the symmetry of the crystal. A definitive source regarding 3-dimensional space groups is the ''International Tables for Crystallography'' . History 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenates
The selenate ion is . Selenates are analogous to sulfates and have similar chemistry. They are highly soluble in aqueous solutions at ambient temperatures. Unlike sulfate, selenate is a somewhat good oxidizer; it can be reduced to selenite or selenium. In strongly acidic conditions, the hydrogen selenate ion, , is formed. It corresponds to the selenic acid, H2SeO4, which is a strong acid and can in its concentrated form dissolve gold. The element selenium exhibits several valence states. Selenate is the least reduced, followed by selenite, and elemental selenium; selenide is even more reduced than elemental selenium. The valence state is an important factor to the toxicity of selenium. Selenate is the form required by organisms that need selenium as a micronutrient. These organisms have the ability to acquire, metabolize and excrete selenium. The level at which selenium becomes toxic varies from species to species and is related to other environmental factors like pH ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenites
Selenite may refer to: Substances containing selenium *A selenium-containing anion or ionic compound with the SeO32− anion: **Selenite (ion), anion is a selenium oxoanion with the chemical formula SeO32− ***Selenous acid, the conjugate acid, with the formula H2SeO3 ***Salts of this anion: **** Silver selenite, an inorganic compound of formula Ag2SeO3 ****Sodium selenite, a salt, a colourless solid, and the most common water-soluble selenium compound *Selenite broth, an enrichment medium for the isolation of ''Salmonella'' species Other * Selenite (mineral), a variety of gypsum (CaSO4·2H2O) * ''Selenites'' is a synonym of ''Zophos'', a genus of land snails in the family Haplotrematidae * Selenite Range, a mountain range in Pershing County, Nevada ** Selenite Peak, a summit in the Selenite Range, Nevada * Selenite, a high class citizen that experienced space travel, from the videogame ''Event_0'' * Selenite, a fictional native inhabitant of the Moon; see Moon in science ficti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
