Wikipedia:WikiProject Chemicals/Chembox validation/VerifiedDataSandbox and Titanium(III) chloride: Difference between pages

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 477000246

| Name = Titanium(III) chloride

| OtherNames = titanium trichloride<br />titanous chloride

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| CASNo_Ref = {{cascite|correct|CAS}}

| UNII_Ref = {{fdacite|changed|FDA}}

| UNII = GVD566MM7K

| PubChem = 62646

| RTECS = XR1924000

| EINECS = 231-728-9

|Section2={{Chembox Properties

| Formula = TiCl₃

| MolarMass = 154.225 g/mol

| Appearance = red-violet crystals <br> [[hygroscopic]]

| Density = 2.64 g/cm³<ref name=":0">{{cite book | last=Eagleson | first=Mary | title=Concise encyclopedia chemistry | publisher=Walter de Gruyter | publication-place=Berlin | date=1994 | isbn=0-89925-457-8 | oclc=29029713}}</ref>

| Solubility = very soluble

| SolubleOther = soluble in [[acetone]], [[acetonitrile]], certain [[amine]]s; <br> insoluble in [[diethyl ether|ether]] and [[hydrocarbon]]s

| MeltingPtC = 440

| MeltingPt_notes = (decomposes)<ref name=":0"/>

| RefractIndex = 1.4856

| MagSus = {{val|+1110.0e-6|u=cm³/mol}}

|Section7={{Chembox Hazards

| ExternalSDS = [https://chemicalsafety.com/sds1/sdsviewer.php?id=30069738&name=Titanium(III)%20chloride External MSDS]

| MainHazards = Corrosive

|Section8={{Chembox Related

| OtherAnions = [[Titanium(III) fluoride]]<br/>[[Titanium(III) bromide]]<br/>[[Titanium(III) iodide]]

| OtherCations = [[Scandium(III) chloride]]<br/>[[Chromium(III) chloride]]<br/>[[Vanadium(III) chloride]]

| OtherCompounds = [[Titanium(IV) chloride]]<br/>[[Titanium(II) chloride]]

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

==Structure and bonding==

In TiCl₃, each titanium atom has one ''d'' electron, rendering its derivatives [[paramagnetic]], that is, the substance is attracted into a magnetic field. Solutions of titanium(III) chloride are violet, which arises from [[Ligand field theory|excitations]] of its [[d-orbital|''d''-electron]]. The colour is not very intense since the transition is [[selection rule|forbidden]] by the [[Laporte selection rule]].

Four solid forms or [[polymorphism (materials science)|polymorphs]] of TiCl₃ are known. All feature titanium in an octahedral coordination sphere. These forms can be distinguished by [[crystallography]] as well as by their magnetic properties, which probes [[exchange interaction]]s. β-TiCl₃ crystallizes as brown needles. Its structure consists of chains of TiCl₆ octahedra that share opposite faces such that the closest Ti–Ti contact is 2.91&nbsp;Å. This short distance indicates strong metal–metal interactions (see figure in upper right). The three violet "layered" forms, named for their color and their tendency to flake, are called alpha (α), gamma (γ), and delta (δ). In α-TiCl₃, the chloride [[anion]]s are [[Close-packing|hexagonal close-packed]]. In γ-TiCl₃, the chlorides anions are [[Cubic crystal system|cubic close-packed]]. Finally, disorder in shift successions, causes an intermediate between alpha and gamma structures, called the δ form. The TiCl₆ share edges in each form, with 3.60&nbsp;Å being the shortest distance between the titanium cations. This large distance between titanium [[cation]]s precludes direct metal-metal bonding. In contrast, the trihalides of the heavier metals [[hafnium]] and [[zirconium]] engage in metal-metal bonding. Direct Zr–Zr bonding is indicated in [[zirconium(III) chloride]]. The difference between the Zr(III) and Ti(III) materials is attributed in part to the relative radii of these metal centers.<ref>{{Greenwood&Earnshaw2nd}}</ref>

Two hydrates of titanium(III) chloride are known, i.e. complexes containing [[aquo ligand]]s. These include the pair of [[hydration isomerism|hydration isomers]] {{chem2|[Ti(H2O)6]Cl3 and [Ti(H2O)4Cl2]Cl(H2O)2}}. The former is violet and the latter, with two molecules of water of crystallization, is green.<ref>{{Greenwood&Earnshaw2nd|page = 965}}</ref>

==Synthesis and reactivity==

TiCl₃ is produced usually by reduction of [[titanium(IV) chloride]]. Older reduction methods used [[hydrogen]]:<ref name= Sherfey>{{cite book |doi=10.1002/9780470132371.ch17|chapter=Titanium(III) Chloride and Titanium(III) Bromide|year=2007|last1=Sherfey|first1=J. M.|title=Inorganic Syntheses|pages=57–61|volume=6|isbn=978-0-470-13237-1}}</ref>

:2&nbsp;TiCl₄ + H₂ → 2&nbsp;HCl + 2&nbsp;TiCl₃

It can also be produced by the reaction of titanium metal and [[hydrochloric acid]].

It is conveniently reduced with [[aluminium]] and sold as a mixture with [[aluminium trichloride]], TiCl₃·AlCl₃. This mixture can be separated to afford TiCl₃([[THF]])₃.<ref>{{cite journal|last1=Jones |first1=N. A. |last2=Liddle |first2=S. T. |last3=Wilson |first3=C. |last4=Arnold |first4=P. L. |title= Titanium(III) Alkoxy-''N''-heterocyclic Carbenes and a Safe, Low-Cost Route to TiCl₃(THF)₃|journal= Organometallics |year= 2007|volume= 26|issue=3 |pages= 755–757|doi= 10.1021/om060486d}}</ref> The complex adopts a meridional structure.<ref>{{cite journal|last1=Handlovic |first1=M. |last2=Miklos |first2=D. |last3=Zikmund |first3=M. |title=The structure of trichlorotris(tetrahydrofuran)titanium(III) |journal=Acta Crystallographica B |date=1981 |volume=37 |issue=4 |pages=811–814 |doi=10.1107/S056774088100438X|bibcode=1981AcCrB..37..811H }}</ref> This light-blue complex TiCl₃(THF)₃ forms when TiCl₃ is treated with [[tetrahydrofuran]] (THF).<ref>{{cite book|last1=Manzer |first1=L. E.|chapter=31. Tetragtdrfuran Complexes of Selected Early Transition Metals |title= Inorganic Syntheses|series= [[Inorganic Syntheses]]|year= 1982|volume= 21|page= 137|doi=10.1002/9780470132524.ch31|isbn=978-0-471-86520-9 }}</ref>

:TiCl₃ + 3 C₄H₈O → TiCl₃(OC₄H₈)₃

An analogous dark green complex arises from complexation with [[dimethylamine]]. In a reaction where all ligands are exchanged, TiCl₃ is a precursor to the blue-colored complex [[Tris(acetylacetonato)titanium(III)|Ti(acac)₃]].<ref>{{cite journal |doi=10.1007/s11224-016-0864-0|title=An Historic and Scientific Study of the Properties of Metal(III) Tris-acetylacetonates|year=2017|last1=Arslan|first1=Evrim|last2=Lalancette|first2=Roger A.|last3=Bernal|first3=Ivan|journal=Structural Chemistry|volume=28|pages=201–212|s2cid=99668641}}</ref>

The more reduced [[titanium(II) chloride]] is prepared by the thermal [[disproportionation]] of TiCl₃ at 500&nbsp;°C. The reaction is driven by the loss of volatile [[Titanium tetrachloride|TiCl₄]]:<ref>{{cite book|last1=Holleman |first1=A. F. |last2=Wiberg |first2=E. |title=Inorganic Chemistry |publisher=Academic Press |location=San Diego, CA |date=2001 |isbn=0-12-352651-5}}{{page needed|date=February 2021}}</ref>

:2 TiCl₃ → TiCl₂ + TiCl₄

The ternary halides, such as A₃TiCl₆, have structures that depend on the cation (A⁺) added.<ref>{{cite journal|last1=Hinz |first1=D. |last2=Gloger |first2=T. |last3=Meyer |first3=G. |title= Ternary halides of the type A₃MX₆. Part 9. Crystal structures of Na₃TiCl₆ and K₃TiCl₆|journal= Zeitschrift für Anorganische und Allgemeine Chemie|year= 2000 |volume= 626|pages= 822–824|doi= 10.1002/(SICI)1521-3749(200004)626:4<822::AID-ZAAC822>3.0.CO;2-6|issue= 4}}</ref> [[Caesium chloride]] treated with titanium(II) chloride and [[hexachlorobenzene]] produces crystalline CsTi₂Cl₇. In these structures Ti³⁺ exhibits octahedral coordination geometry.<ref>{{cite journal|last1=Jongen |first1=L. |last2=Meyer |first2=G. |title= Caesium heptaiododititanate(III), CsTi₂I₇|journal= Zeitschrift für Anorganische und Allgemeine Chemie|year= 2004 |volume= 630|pages= 211–212|doi= 10.1002/zaac.200300315|issue= 2}}</ref>

==Applications==

TiCl₃ is the main [[Ziegler–Natta catalyst]], responsible for most industrial production of [[polyethylene]]. The catalytic activities depend strongly on the polymorph of the TiCl₃ (α vs. β vs. γ vs. δ) and the method of preparation.<ref>{{Ullmann|first1=Kenneth S. |last1=Whiteley |first2=T. Geoffrey |last2=Heggs |first3=Hartmut |last3=Koch |first4=Ralph L. |last4=Mawer |first5=Wolfgang |last5=Immel |title=Polyolefins |year=2005 |doi=10.1002/14356007.a21_487}}</ref>

===Laboratory use===

TiCl₃ is also a specialized [[reagent]] in organic synthesis, useful for reductive coupling reactions, often in the presence of added reducing agents such as zinc. It reduces [[oxime]]s to [[imine]]s.<ref>{{cite encyclopedia|first1=Lise-Lotte |last1=Gundersen |first2=Frode |last2=Rise |first3=Kjell |last3=Undheim |first4=José |last4=Méndez Andino |title=Titanium(III) Chloride |encyclopedia=[[Encyclopedia of Reagents for Organic Synthesis]] |year=2007 |doi=10.1002/047084289X.rt120.pub2|isbn=978-0-471-93623-7 }}</ref> Titanium trichloride can reduce nitrate to ammonium ion thereby allowing for the sequential analysis of nitrate and ammonia.<ref>{{cite journal|title=Determining Ammonium & Nitrate ions using a Gas Sensing Ammonia Electrode |journal=Soil and Crop Science Society of Florida |volume=65 |date=2006 |first1=D. W. |last1=Rich |first2=B. |last2=Grigg |first3=G. H. |last3=Snyder}}</ref> Slow deterioration occurs in air-exposed titanium trichloride, often resulting in erratic results, such as in reductive [[coupling reaction]]s.<ref name=OrgSyn>{{OrgSynth|year=1981|last1= Fleming|first1= Michael P.|last2= McMurry|first2=John E. |title= Reductive Coupling of Carbonyls to Alkenes: Adamantylideneadamantane|volume = 60|pages = 113|doi = 10.15227/orgsyn.060.0113}}</ref>

==Safety==

TiCl₃ and most of its complexes are typically handled under [[air-free conditions]] to prevent reactions with oxygen and moisture. Samples of TiCl₃ can be relatively air stable or [[pyrophoricity|pyrophoric]].<ref name="IngrahamDownes1957">{{cite journal|last1=Ingraham|first1=T. R.|last2=Downes|first2=K. W.|last3=Marier|first3=P.|title=The Production of Titanium Trichloride by Arc-Induced Hydrogen Reduction of Titanium Tetrachloride|journal=Canadian Journal of Chemistry|volume=35|issue=8|year=1957|pages=850–872|issn=0008-4042|doi=10.1139/v57-118}}</ref><ref name="Pohanish2009">{{cite book|title=Wiley Guide to Chemical Incompatibilities|last1=Pohanish |first1=Richard P. |last2=Greene |first2=Stanley A. |publisher=John Wiley & Sons|year=2009|edition=3rd|isbn=978-0-470-52330-8|page=1010}}</ref>

==References==

{{reflist|30em}}

{{Titanium compounds}}

{{Chlorides}}

[[Category:Titanium(III) compounds]]

[[Category:Chlorides]]

[[Category:Titanium halides]]

[[Category:Reducing agents]]