In chemistry an antimonate is a compound which contains a
metallic element
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...
,
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
, and
antimony
Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient time ...
in an
oxidation state
In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...
of +5. These compounds adopt polymeric structures with M-O-Sb linkages. They can be considered to be derivatives of the hypothetical
antimonic acid
Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient times ...
H
3SbO
4, or combinations of
metal oxide
An oxide () is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. with oxygen in the oxidation state of −2. Most of the E ...
s and
antimony pentoxide
Antimony pentoxide (molecular formula: Sb2O5) is a chemical compound of antimony and oxygen. It contains antimony in the +5 oxidation state.
Structure
Antimony pentoxide has the same structure as the ''B'' form of niobium pentoxide and can be deri ...
, Sb
2O
5.
Historically these compounds were assumed to be analogous to the phosphates and formulas such as LiSbO
3·3H
2O and Na
2H
2Sb
2O
7·5H
2O were used and the compounds described as hydrated meta-antimonates and pyro-antimonates. LiSbO
3·3H
2O is now known to be LiSb(OH)
6 and contain the anion and that Na
2H
2Sb
2O
7·5H
2O is actually NaSb(OH)
6.
[ Wells A.F. (1984) ''Structural Inorganic Chemistry'' 5th edition, Oxford Science Publications ]
Some examples of antimonates and their structures are shown below:
*Li
3SbO
4 has a
NaCl
Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...
superstructure with isolated units.
*Sodium antimonate, NaSbO
3, has the
ilmenite
Ilmenite is a titanium-iron oxide mineral with the idealized formula . It is a weakly magnetic black or steel-gray solid. Ilmenite is the most important ore of titanium and the main source of titanium dioxide, which is used in paints, printing ...
structure, with hexagonal close packed oxide ions with each ion, Na
+ and Sb
5+ occupying a third of the octahedral sites.
*MgSb
2O
6 has the trirutile structure, which is similar to the
rutile
Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer Polymorphism (materials science), polymorphs of TiO2 are known, including anatase, akaogiite, and brookite.
Rutile has one of the highest ...
structure except that there are two different cations in the lattice.
*AlSbO
4 has the
rutile
Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer Polymorphism (materials science), polymorphs of TiO2 are known, including anatase, akaogiite, and brookite.
Rutile has one of the highest ...
structure with random occupancy.
*Lead antimonate, Pb
2Sb
2O
7,
Naples yellow, has the
pyrochlore
Pyrochlore () is a mineral group of the niobium end member of the pyrochlore supergroup.
The general formula, (where A and B are metals), represent a family of phases isostructural to the mineral pyrochlore.
Pyrochlores are an important class of ...
structure.
*Calcium antimonate, Ca
2Sb
2O
7, has the
weberite structure.
*Ferric ortho-antimonate, Fe
2O
3·Sb
2O
5 or
FeSbO4, has the
rutile
Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer Polymorphism (materials science), polymorphs of TiO2 are known, including anatase, akaogiite, and brookite.
Rutile has one of the highest ...
structure with random occupancy.
Antimonate in chemical nomenclature
IUPAC recommendations are that compounds with anions containing antimony(V) have the antimonate(V) suffix or antimonate followed by a charge number, for example the ion would be called hexahydridoxidoantimonate(V) or alternatively hexahydroxidoantimonate(1−).
[Nomenclature of Inorganic Chemistry—IUPAC Recommendations 200]
Red Book 2005.pdf
/ref>
See also
*Antimonate mineral
Antimonate minerals are those minerals containing the antimonate (SbO43−) anion group. Both the Dana and the Strunz mineral classifications place the antimonates in with the phosphate minerals
Phosphate minerals contain the tetrahedrally coord ...
*Antimonide Antimonides (sometimes called stibnides) are compounds of antimony with more electropositive elements. The antimonide ion
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative b ...
*Antimonite
In chemistry, antimonite refers to a salt of antimony(III), such as NaSb(OH)4 and NaSbO2 (meta-antimonite), which can be prepared by reacting alkali with antimony trioxide, Sb2O3.Egon Wiberg, Arnold Frederick Holleman (2001) ''Inorganic Chemist ...
References
{{Reflist
Antimony(V) compounds
Oxyanions
Oxometallates