# Titanium(III) iodide

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Names Identifiers IUPAC name Titanium(III) iodide Other names Titanium triiodide 3D model (JSmol) I[Ti](I)I I3Ti Molar mass 428.580 g·mol−1 Appearance black-violet solid Density 4.96 g·cm−3 [1] Other anions Titanium(III) bromide Titanium(III) chloride Titanium(III) fluoride Related compounds Titanium(IV) iodide Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Titanium(III) iodide is an inorganic compound with the formula TiI3. It is a dark violet solid that is insoluble in solvents, except upon decomposition.

An inorganic compound is typically a chemical compound that lacks C-H bonds, that is, a compound that is not an organic compound, but the distinction is not defined or even of particular interest.

## Preparation and structure

Titanium(III) iodide can be prepared by reaction of titanium with iodine: [2]

Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a lustrous, purple-black non-metallic solid at standard conditions that melts to form a deep violet liquid at 114 degrees Celsius, and boils to a violet gas at 184 degrees Celsius. The element was discovered by the French chemist Bernard Courtois in 1811. It was named two years later by Joseph Louis Gay-Lussac from this property, after the Greek ἰώδης "violet-coloured".

${\displaystyle \mathrm {2\ Ti+3\ I_{2}\longrightarrow 2\ TiI_{3}} }$

It can also be obtained by reduction of TiI4, e.g., with aluminium . [3]

Aluminium is a chemical element with the symbol Al and atomic number 13. It is a silvery-white, soft, non-magnetic and ductile metal in the boron group. By mass, aluminium makes up about 8% of the Earth's crust; it is the third most abundant element after oxygen and silicon and the most abundant metal in the crust, though it is less common in the mantle below. The chief ore of aluminium is bauxite. Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is found combined in over 270 different minerals.

In terms of its structure, the compound exists as a polymer of face-sharing octahedra. Above 323 K, the Ti---Ti spacing are equal, but below that temperature, the material undergoes a phase transition. In the low temperature phase, the Ti---Ti contacts are alternating short and long. The low temperature structure is similar to that of molybdenum tribromide. [1]

The term phase transition is most commonly used to describe transitions between solid, liquid, and gaseous states of matter, as well as plasma in rare cases. A phase of a thermodynamic system and the states of matter have uniform physical properties. During a phase transition of a given medium, certain properties of the medium change, often discontinuously, as a result of the change of external conditions, such as temperature, pressure, or others. For example, a liquid may become gas upon heating to the boiling point, resulting in an abrupt change in volume. The measurement of the external conditions at which the transformation occurs is termed the phase transition. Phase transitions commonly occur in nature and are used today in many technologies.

## Related Research Articles

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In chemistry, titanate usually refers to inorganic compounds composed of titanium oxides. In some cases, the term is used more generally for any titanium-containing anion, e.g. [TiCl6]2− and [Ti(CO)7]2−. This article focuses on the oxides.

Silver iodide is an inorganic compound with the formula AgI. The compound is a bright yellow solid, but samples almost always contain impurities of metallic silver that give a gray coloration. The silver contamination arises because AgI is highly photosensitive. This property is exploited in silver-based photography. Silver iodide is also used as an antiseptic and in cloud seeding.

An intermetallic is a type of metallic alloy that forms a solid-state compound exhibiting defined stoichiometry and ordered crystal structure.

Thermochromism is the property of substances to change color due to a change in temperature. A mood ring is an excellent example of this phenomenon, but thermochromism also has more practical uses, such as baby bottles which change to a different color when cool enough to drink, or kettles which change when water is at or near boiling point. Thermochromism is one of several types of chromism.

A chalcogenide is a chemical compound consisting of at least one chalcogen anion and at least one more electropositive element. Although all group 16 elements of the periodic table are defined as chalcogens, the term chalcogenide is more commonly reserved for sulfides, selenides, tellurides, and polonides, rather than oxides. Many metal ores exist as chalcogenides. Photoconductive chalcogenide glasses are used in xerography. Some pigments and catalysts are also based on chalcogenides. The metal dichalcogenide MoS2 is a common solid lubricant.

Titanium(III) chloride is the inorganic compound with the formula TiCl3. At least four distinct species have this formula; additionally hydrated derivatives are known. TiCl3 is one of the most common halides of titanium and is an important catalyst for the manufacture of polyolefins.

Titanium tetraiodide is an inorganic compound with the formula TiI4. It is a black volatile solid, first reported by Rudolph Weber in 1863. It is an intermediate in the Van Arkel process for the purification of titanium.

Vanadium(III) bromide, also known as vanadium tribromide, is VBr3. In the solid-state, this species is a polymeric with octahedral vanadium(III) surrounded by six bromide ligands.

Thallium(I) iodide is a chemical compound with the formula TlI. It is unusual in being one of the few water-insoluble metal iodides, along with AgI, CuI, SnI2, SnI4, PbI2 and HgI2.

Titanium hydride normally refers to the inorganic compound TiH2 and related nonstoichiometric materials. It is commercially available as a stable grey/black powder, which is used as an additive in the production of Alnico sintered magnets, in the sintering of powdered metals, the production of metal foam, the production of powdered titanium metal and in pyrotechnics.

Titanium(II) oxide (TiO) is an inorganic chemical compound of titanium and oxygen. It can be prepared from titanium dioxide and titanium metal at 1500 °C. It is non-stoichiometric in a range TiO0.7 to TiO1.3 and this is caused by vacancies of either Ti or O in the defect rock salt structure. In pure TiO 15% of both Ti and O sites are vacant. Careful annealing can cause ordering of the vacancies producing a monoclinic form which has 5 TiO units in the primitive cell that exhibits lower resistivity. A high temperature form with titanium atoms with trigonal prismatic coordination is also known. Acid solutions of TiO are stable for a short time then decompose to give hydrogen:

Titanium(III) phosphide (TiP) is an inorganic chemical compound of titanium and phosphorus. Normally encountered as a grey powder, it is a metallic conductor with a high melting point. It is not attacked by common acids or water. Its physical properties stand in contrast to the group 1 and group 2 phosphides that contain the P3− anion (such as Na3P), which are not metallic and are readily hydrolysed. Titanium phosphide is classified as a "metal-rich phosphide", where extra valence electrons from the metal are delocalised.

Antimony triiodide is the chemical compound with the formula SbI3. This ruby-red solid is the only characterized "binary" iodide of antimony, i.e. the sole compound isolated with the formula SbxIy. It contains antimony in its +3 oxidation state. Like many iodides of the heavier main group elements, its structure depends on the phase. Gaseous SbI3 is a molecular, pyramidal species as anticipated by VSEPR theory. In the solid state, however, the Sb center is surrounded by an octahedron of six iodide ligands, three of which are closer and three more distant. For the related compound BiI3, all six Bi—I distances are equal.

Calcium titanate is an inorganic compound with the chemical formula CaTiO3. As a mineral, it is called perovskite, named after Russian mineralogist, L. A. Perovski (1792-1856). It is a colourless, diamagnetic solid, although the mineral is often coloured owing to impurities.

Few compounds of californium have been made and studied. The only californium ion that is stable in aqueous solutions is the californium(III) cation. The other two oxidation states are IV (strong oxidizing agents) and II (strong reducing agents). The element forms a water-soluble chloride, nitrate, perchlorate, and sulfate and is precipitated as a fluoride, oxalate or hydroxide. If problems of availability of the element could be overcome, then CfBr2 and CfI2 would likely be stable.

Titanium disulfide is an inorganic compound with the formula TiS2. A golden yellow solid with high electrical conductivity, it belongs to a group of compounds called transition metal dichalcogenides, which consist of the stoichiometry ME2. TiS2 has been employed as a cathode material in rechargeable batteries.

Molybdenum(III) bromide is the inorganic compound with the formula MoBr3. It is a black solid that is insoluble in most solvents but dissolves in donor solvents such as pyridine.

Bismuth titanate or bismuth titanium oxide is a solid inorganic compound of bismuth, titanium and oxygen with the chemical formula of Bi12TiO20, Bi 4Ti3O12 or Bi2Ti2O7

Alexander Knyazev is a Russian crystal chemist and physical chemist, Professor of the Lobachevsky University, Dean of the Chemical Faculty. Head of the Department of Medicinal Chemistry, Head of the postgraduate research school "New materials based on inorganic compounds." He graduated from the Faculty of Chemistry, Lobachevsky University (1998) and PhD (2000), Doctor of Chemistry (2009), academic rank of professor (2011).

## References

1. Joachim Angelkort, Andreas Schoenleber, Sander van Smaalen: Low- and high-temperature crystal structures of. In: Journal of Solid State Chemistry. 182, 2009, S. 525–531, doi : 10.1016/j.jssc.2008.11.028.
2. F. Hein, S. Herzog "Molybdenum(III) Bromide" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 1407.
3. Catherine E. Housecroft, A. G. Sharpe (2005), Inorganic Chemistry (in German), Pearson Education, p. 601, ISBN   0-13039913-2