Vanadium(II) sulfide

Vanadium(II) sulfide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.032.096
EC Number
  • 235-319-6
  • InChI=1S/S.V
    Key: ZFDNHUHPLXMMBR-UHFFFAOYSA-N
  • S=[V]
Properties
SV
Molar mass 83.00 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Vanadium(II) sulfide (also vanadium monosulfide) is an inorganic compound with the chemical formula VS.[1]

Properties

On heating to between 1,700–2,000 K (1,430–1,730 °C; 2,600–3,140 °F) VS evaporates forming VS molecules as well as atomic sulfur S and atomic vanadium V. Some VS2 and S2 molecules also appear in the gas phase.[2]

The ground state of the VS molecule is C4Σ−; it has a dipole moment of 2.38 D. The excited state X4Σ− has a dipole moment of 5.16 D.[3]

Bonding in VS is mostly covalent, and little charge is transferred from the vanadium atoms to the sulfur.[4]

Structure

Vanadium monosulfide has two different crystal structures, exhibiting dimorphism. The NiAs type is hexagonal (space group P63/mmc) while the MnP type is orthorhombic (s.g. Pcmm). The crystal form and unit cell dimensions vary with the sulfur to vanadium ratio. At the stoichiometric ratio, the stable structure is orthorhombic.[5] As the S:V ratio increases, the c parameter decreases linearly. Over about S:V = 1.03 the b parameter increases and the a parameter decreases, suddenly converging to each other on 3.34 Å at a S:V ratio of 1.06. The most sulfur deficient orthorhombic form has the composition S0.93V.

The crystal structure accommodates variations in the sulfur to vanadium ratio, by including vacancies. This means that the densest form is VS with a density of 4.90 g/cm3 while non-stoichiometric forms are less dense.[6] Stoichimetric VS has the unit cell dimensions a = 5.825, b = 3.310 and c = 5.854 Å.[1]

Stoichiometric VS changes crystal form at 630 °C (903 K; 1,166 °F) to the hexagonal form.[4]

Preparation

Vanadium monosulfide can be made by heating a mixture of finely powdered sulfur and vanadium in the correct ratio.[1]

In VS, vanadium can be substituted by titanium (VxTi1-xS) in solid solution. Also, sulfur can be substituted by selenium (VSxSe1-x).[4]

Other vanadium sulfides include V3S, V5S4, V7S8, V3S4, V5S8 V2S3, VS2, VS4.[1]

Ternary sulfides containing vanadium in the +2 oxidation state include VSc2S4, VTi2S4 and VCr2S4.[7][8]

References

  1. ^ a b c d Rao, C.N.R.; Pisharody, K.P.R. (January 1976). "Transition metal sulfides". Progress in Solid State Chemistry. 10: 207–270. doi:10.1016/0079-6786(76)90009-1.
  2. ^ Owzarski, Thomas P.; Franzen, Hugo F. (1 February 1974). "High temperature mass spectrometry, vaporization, and thermodynamics of vanadium monosulfide". The Journal of Chemical Physics. 60 (3): 1113–1117. doi:10.1063/1.1681122.
  3. ^ Zhuang, Xiujuan; Steimle, Timothy C. (2010-06-21). "The permanent electric dipole moment of vanadium monosulfide". The Journal of Chemical Physics. 132 (23). doi:10.1063/1.3454722. ISSN 0021-9606.
  4. ^ a b c Lewis, L.Henderson; Goodenough, J.B. (February 1995). "The Crystal Chemistry and Role of Metal-Metal Bonding in the Monochalcogenides TiS, VS, TiSe, and VSe and Their Solid Solutions". Journal of Solid State Chemistry. 114 (2): 342–345. doi:10.1006/jssc.1995.1054.
  5. ^ Franzen, Hugo F.; Westman, Sven; Sunner, S.; Hatanaka, Akikazu; Munch-Petersen, Jon (1963). "A New Vanadium Monosulfide". Acta Chemica Scandinavica. 17: 2353–2354. doi:10.3891/acta.chem.scand.17-2353.
  6. ^ Franzen, H. F.; Burger, T. J. (1 September 1968). "Second-Order Phase Transition in the VS One-Phase Region". The Journal of Chemical Physics. 49 (5): 2268–2272. doi:10.1063/1.1670395.
  7. ^ Holt, S.L.; Bouchard, R.J.; Wold, A. (April 1966). "Ternary chalcogenides of vanadium and chromium". Journal of Physics and Chemistry of Solids. 27 (4): 755–759. doi:10.1016/0022-3697(66)90227-7.
  8. ^ Hulliger, F. (1968). "Crystal chemistry of the chalcogenides and pnictides of the transition elements". Structure and Bonding. 4: 83–229. doi:10.1007/BFb0119186.
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