Titanium compounds

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See also the categories Titanium compounds and Titanium minerals
A steel colored twist drill bit with the spiral groove colored in a golden shade.
TiN-coated drill bit

The +4

octahedral coordination geometry in its complexes,[3][4] but tetrahedral TiCl4 is a notable exception. Because of its high oxidation state, titanium(IV) compounds exhibit a high degree of covalent bonding.[1]

Oxides, sulfides, and alkoxides

Titanium dioxide powder

The most important oxide is TiO2, which exists in three important

polymorphs; anatase, brookite, and rutile. All three are white diamagnetic solids, although mineral samples can appear dark (see rutile). They adopt polymeric structures in which Ti is surrounded by six oxide ligands that link to other Ti centers.[5]

The term

asterism (star-forming shine) from the presence of titanium dioxide impurities.[7]

A variety of reduced oxides (

reduction of TiO2 with hydrogen at high temperatures,[8] and is used industrially when surfaces need to be vapor-coated with titanium dioxide: it evaporates as pure TiO, whereas TiO2 evaporates as a mixture of oxides and deposits coatings with variable refractive index.[9] Also known is Ti2O3, with the corundum structure, and TiO, with the rock salt structure, although often nonstoichiometric.[10]

The

sol-gel process. Titanium isopropoxide is used in the synthesis of chiral organic compounds via the Sharpless epoxidation.[11]

Titanium forms a variety of sulfides, but only

lithium batteries. Because Ti(IV) is a "hard cation", the sulfides of titanium are unstable and tend to hydrolyze to the oxide with release of hydrogen sulfide.[12]

Nitrides and carbides

semiconductor fabrication.[16] Titanium carbide (TiC), which is also very hard, is found in cutting tools and coatings.[17]

Halides

titanium trichloride
.

Mukaiyama aldol condensation.[20] In the van Arkel–de Boer process, titanium tetraiodide (TiI4) is generated in the production of high purity titanium metal.[21]

Titanium(III) and titanium(II) also form stable chlorides. A notable example is

catalyst for production of polyolefins (see Ziegler–Natta catalyst) and a reducing agent in organic chemistry.[22]

Organometallic complexes

Main article: Organotitanium chemistry

Owing to the important role of titanium compounds as polymerization catalyst, compounds with Ti-C bonds have been intensively studied. The most common organotitanium complex is titanocene dichloride ((C5H5)2TiCl2). Related compounds include Tebbe's reagent and Petasis reagent. Titanium forms carbonyl complexes, e.g. (C5H5)2Ti(CO)2.[23]

Anticancer therapy studies

Following the success of platinum-based chemotherapy, titanium(IV) complexes were among the first non-platinum compounds to be tested for cancer treatment. The advantage of titanium compounds lies in their high efficacy and low toxicity in vivo.[24] In biological environments, hydrolysis leads to the safe and inert titanium dioxide. Despite these advantages the first candidate compounds failed clinical trials due to insufficient efficacy to toxicity ratios and formulation complications.[24] Further development resulted in the creation of potentially effective, selective, and stable titanium-based drugs.[24]

See also

References

  1. ^ a b Greenwood & Earnshaw 1997, p. 958
  2. ^ Greenwood & Earnshaw 1997, p. 970
  3. ^ Greenwood & Earnshaw 1997, p. 960
  4. ^ Greenwood & Earnshaw 1997, p. 967
  5. ^ Greenwood & Earnshaw 1997, p. 961
  6. ISBN 978-0-7876-5015-5
    .
  7. ISBN 978-0-19-850340-8
    .
  8. doi:10.3724/SP.J.1077.2013.12309
    .
  9. S2CID 119213226
    .
  10. ^ Greenwood & Earnshaw 1997, p. 962.
  11. PMID 16771446
    .
  12. ISBN 9780470132616
    .
  13. doi:10.1063/1.351465
    .
  14. ^ Schubert, E.F. "The hardness scale introduced by Friederich Mohs" (PDF). Educational resources. Troy, NY: Rensselaer Polytechnic Institute. Archived (PDF) from the original on 3 June 2010.
  15. ISSN 0032-4558
    .
  16. ISBN 978-981-256-605-8
    .
  17. ^ "Titanium carbide product information". H.C. Starck. Archived from the original on 22 September 2017. Retrieved 16 November 2015.
  18. ISBN 978-0-8330-4575-1
    .
  19. ISBN 978-3-540-64612-9
    .
  20. ISBN 978-0-470-85625-3
    .
  21. ^ Greenwood & Earnshaw 1997, p. 965
  22. ISBN 978-0471936237
    .
  23. ISBN 978-1891389535
    .
  24. ^
    PMID 29394027. {{cite book}}: |journal= ignored (help
    )

Works cited
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