Chemistry:Vanadium(III) iodide

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Vanadium(III) iodide
Names
IUPAC name
Vanadium(III) iodide
Other names
Vanadium triiodide
Identifiers
3D model (JSmol)
Properties
VI3
Molar mass 431.6549 g/mol
Appearance black solid
Density 5.14 g/cm3, solid
soluble
Structure
octahedral
Related compounds
Other anions
Vanadium(III) bromide
Other cations
Titanium(III) iodide
Related compounds
VI2
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Vanadium(III) iodide is the inorganic compound with the formula VI3. This paramagnetic solid is generated by the reaction of vanadium powder with iodine at around 500 °C.[1] The black hygroscopic crystals dissolve in water to give green solutions, characteristic of V(III) ions.

The purification of vanadium metal by the chemical transport reaction involving the reversible formation of vanadium(III) iodides in the presence of iodine and its subsequent decomposition to yield pure metal:

2 V + 3 I2 ⇌ 2 VI3

VI3 crystallizes in the motif adopted by bismuth(III) iodide: the iodides are hexagonal-closest packed and the vanadium centers occupy one third of the octahedral holes.

When solid samples are heated, the gas contains VI4, which is probably the volatile vanadium component in the vapor transport method. Thermal decomposition of the triiodide leaves a residue of vanadium(II) iodide:[2]

2 VI3 → VI2 + VI4 ΔH = 36.6 kcal/mol; ΔS = 38.7 e.u.

References

  1. Juza, D.; Giegling, D.; Schäfer, H. (1969). "Über die Vanadiniodide VJ2 und VJ3". Z. Anorg. Allg. Chem. 366 (3–4): 121–9. doi:10.1002/zaac.19693660303. 
  2. Berry, K. O.; Smardzewski, R. R.; McCarley, R. E. (1969). "Vaporization reactions of vanadium iodides and evidence for gaseous vanadium(IV) iodide". Inorg. Chem. 8 (9): 1994–7. doi:10.1021/ic50079a034. 
HI He
LiI BeI2 BI3 CI4 NI3 I2O4,
I2O5,
I4O9
IF,
IF3,
IF5,
IF7
Ne
NaI MgI2 AlI3 SiI4 PI3,
P2I4
S ICl,
ICl3
Ar
KI CaI2 Sc TiI4 VI3 CrI3 MnI2 FeI2 CoI2 NiI2 CuI ZnI2 Ga2I6 GeI2,
GeI4
AsI3 Se IBr Kr
RbI SrI2 YI3 ZrI4 NbI5 Mo Tc Ru Rh Pd AgI CdI2 InI3 SnI4,
SnI2
SbI3 TeI4 I Xe
CsI BaI2   HfI4 TaI5 W Re Os Ir Pt AuI Hg2I2,
HgI2
TlI PbI2 BiI3 Po AtI Rn
Fr RaI2   Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
La Ce Pr Nd Pm SmI2 Eu Gd TbI3 Dy Ho Er Tm Yb Lu
Ac ThI4 Pa UI3,
UI4
Np Pu Am Cm Bk Cf EsI3 Fm Md No Lr