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In [[chemistry]], '''titanate''' usually refers to [[inorganic compound]]s composed of [[titanium oxide]]s, or [[oxide]]s containing the [[titanium]] element. Together with [[niobate]], titanate salts form the [[perovskite (structure)|Perovskite group]].

In some cases, the term is used more generally for any titanium-containing [[anion]], e.g. [TiCl<sub>6</sub>]<sup>2−</sup> and [Ti(CO)<sub>6</sub>]<sup>2−</sup>. This article focuses on the oxides.

Many kinds of titanium oxides are known, and some are commercially important. Typically these materials are white, [[diamagnetic]], high-melting, and insoluble in water. They are often prepared at high temperatures, e.g. using [[tube furnace]]s, from titanium dioxide. In virtually all cases, titanium achieves [[octahedral coordination geometry]].<ref name="G&E">{{Greenwood&Earnshaw1st|pages=1121–23}}.</ref>

==Orthotitanates==
Orthotitanates have the formula M<sub>2</sub>TiO<sub>4</sub>, where M is divalent. An example of such a material is magnesium titanate (Mg<sub>2</sub>TiO<sub>4</sub>), which adopts the [[Spinel group|spinel structure]]. Li<sub>2</sub>TiO<sub>3</sub> is not considered an orthotitanate since it adopts the [[Cubic crystal system#Rock-salt structure|rock-salt structure]] and does not feature an identifiable titanium anion. Orthotitanates almost never feature identifiable TiO<sub>4</sub><sup>4−</sup> centres, an exception being [[Barium orthotitanate|Ba<sub>2</sub>TiO<sub>4</sub>]].<ref>{{cite journal|last=Wu|first=Kang Kun|author2=Brown, I. D. |title=The Crystal Structure of β-Barium Orthotitanate, β-Ba<sub>2</sub>TiO<sub>4</sub>, and the Bond Strength-Bond Length Curve of Ti-O|journal=Acta Crystallographica|date=10 April 1973|volume=B29|pages=2009–2012|doi=10.1107/S0567740873005959}}</ref>

===Titanic acid and its esters===
Also called orthotitanic acid or titanium hydroxide, the substance H<sub>4</sub>TiO<sub>4</sub> is called [[titanic acid]]. This material, which is not well defined, is obtained by hydrolysis of TiCl<sub>4</sub>.<ref>Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 421.</ref> The solid is unstable with respect to loss of water and formation of titanium dioxide. [[Esters]] of orthotitanic acid are known, however; one example being [[titanium isopropoxide]]. Esters derived from smaller alcohols adopt more complex structures wherein titanium does achieve octahedral coordination, e.g. Ti<sub>4</sub>(OCH<sub>3</sub>)<sub>16</sub> or titanium tetramethoxide.<ref>D. A. Wright and D. A. Williams "The crystal and molecular structure of titanium tetramethoxide" Acta Crystallogr. B 1968, volume 24, pp. 1107-1114. {{doi|10.1107/S0567740868003766}}.</ref> It is a weak acid, if it can be isolated.

==Metatitanates==
The metatitanates have the formula MTiO<sub>3</sub>, where again M is divalent. They do not feature discrete TiO<sub>3</sub><sup>2−</sup> centres. Some, like the commercially important mineral [[ilmenite]] (FeTiO<sub>3</sub>), crystallize in the [[Close-packing of spheres|hexagonal close packing]] motif seen in [[corundum]]. Alternatively, some materials with the formula MTiO<sub>3</sub> crystallize in the motif known as [[Perovskite (structure)|perovskite]], which is also the name of the mineral form of [[calcium titanate]] (CaTiO<sub>3</sub>). [[Barium titanate]] is one such perovskite-structured titanate with [[ferroelectric]] properties.<ref name="G&E"/>

==Complex titanates==
More complex titanates are also known, such as [[bismuth titanate]], Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub>.<ref>{{citation | last1 = Galasso | first1 = F. S. | last2 = Kestigan | first2 = M. | year = 2007 | title = Bismuth Titanate, Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub> | journal = Inorg. Synth. | volume = 30 | pages = 121 | doi = 10.1002/9780470132616.ch24}}.</ref>

==References==
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{{Hydrogen compounds}}
{{Titanium compounds}}

[[Category:Titanates| ]]
[[Category:Transition metal oxyanions]]
[[Category:Oxometallates]]