chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a natural science that covers the elements that make up matter to the compounds made of atoms, molecules and ions: their composition, structure, propertie ...

, titanate usually refers to

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistr ...

s composed of

titanium oxide Titanium oxide may refer to: * Titanium dioxide (titanium(IV) oxide), TiO2 * Titanium(II) oxide (titanium monoxide), TiO, a non-stoichiometric oxide * Titanium(III) oxide (dititanium trioxide), Ti2O3 * Ti3O * Ti2O * δ-TiOx (x= 0.68–0.75) * Ti ...

s. Together with niobate, titanate salts form the Perovskite group. In some cases, the term is used more generally for any titanium-containing

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 convent ...

, e.g. iCl₆sup>2− and i(CO)₆sup>2−. This article focuses on the oxides. Many kinds of titanium oxides are known, and some are commercially important. Typically these materials are white,

diamagnetic Diamagnetic materials are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. In contrast, paramagnetic and ferromagnetic materials are attracted ...

, high-melting, and insoluble in water. They are often prepared at high temperatures, e.g. using tube furnaces, from titanium dioxide. In virtually all cases, titanium achieves

octahedral coordination geometry In chemistry, octahedral molecular geometry, also called square bipyramidal, describes the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. The oc ...

Orthotitanates

Orthotitanates have the formula M₂TiO₄, where M is divalent. An example of such a material is magnesium titanate (Mg₂TiO₄), which adopts the

spinel structure The spinels are any of a class of minerals of general formulation which crystallise in the cubic (isometric) crystal system, with the X anions (typically chalcogens, like oxygen and sulfur) arranged in a cubic close-packed lattice and the cation ...

. Li₂TiO₃ is not considered an orthotitanate since it adopts the

rock-salt structure Halite (), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride ( Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, p ...

and does not feature an identifiable titanium anion. Orthotitanates almost never feature identifiable TiO₄⁴⁻ centres, an exception being Ba₂TiO₄.

Titanic acid and its esters

Also called orthotitanic acid or titanium hydroxide, the substance H₄TiO₄ is called titanic acid. This material, which is not well defined, is obtained by hydrolysis of TiCl₄. The solid is unstable with respect to loss of water and formation of titanium dioxide.

Esters In chemistry, an ester is a chemical compound, compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an Alcohol ...

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. Ti₄(OCH₃)₁₆ or titanium tetramethoxide. It is a weak acid, if it can be isolated.

Metatitanates

The metatitanates have the formula MTiO₃, where again M is divalent. They do not feature discrete TiO₃²⁻ centres. Some, like the commercially important mineral

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 ...

(FeTiO₃), crystallize in the

hexagonal close packing In geometry, close-packing of equal spheres is a dense arrangement of congruent spheres in an infinite, regular arrangement (or lattice). Carl Friedrich Gauss proved that the highest average density – that is, the greatest fraction of space occ ...

motif seen in

corundum Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium and chromium. It is a rock-forming mineral. It is a naturally transparent material, but can have different colors depending on the pre ...

. Alternatively, some materials with the formula MTiO₃ crystallize in the motif known as

perovskite Perovskite (pronunciation: ) is a calcium titanium oxide mineral composed of calcium titanate (chemical formula ). Its name is also applied to the class of compounds which have the same type of crystal structure as (XIIA2+VIB4+X2−3), known as ...

, which is also the name of the mineral form of calcium titanate (CaTiO₃).

Barium titanate Barium titanate (BTO) is an inorganic compound with chemical formula BaTiO3. Barium titanate appears white as a powder and is transparent when prepared as large crystals. It is a ferroelectric, pyroelectric, and piezoelectric ceramic material th ...

is one such perovskite-structured titanate with

ferroelectric Ferroelectricity is a characteristic of certain materials that have a spontaneous electric polarization that can be reversed by the application of an external electric field. All ferroelectrics are also piezoelectric and pyroelectric, with the ad ...

properties.

Complex titanates

More complex titanates are also known, such as bismuth titanate, Bi₄Ti₃O₁₂..

References

{{Titanium compounds Transition metal oxyanions Oxometallates