Vanadium (IV) tetrachloride VCl4 is red-brown liquid, melting point –28 °C, boiling point 150 °C. Vanadium tetrachloride forms Lewis-base adducts like VCl4 x 2L (L = 2-electron donor)).
VCl4 is synthesized by direct reaction of vanadium metal with chlorine (with intermediate formation of VCl2):
V + n Cl2 → VCl2 (n = 1) / VCl4 (n = 2)
Vanadium tetrachloride VCl4 has been applied as precursor for the preparation of pure metallic vanadium V by thermal induced decomposition (thermal CVD).
VCl4 has been applied as precursor for the deposition of pure metallic V and V/(Ti, Nb) alloys at 850 – 900 °C temperatures in presence of H2 and He by thermal decomposition of the halides (including VCl4) formed by passing a stream of Cl2 over the respective metal chips (V, Ti, Nb).
VCl4 (combined with water as co-reactant) was applied as precursor for the growth of thin films of vanadium oxide (VOx) on glass substrates by APCVD at 450°C
temperature. The influence of VCl4/ H2O ratio on layer morphological and structural properties was studied. It was determined that vanadium oxidation state and film morphological characteristics were strongly affected by H2O concentration; the achievement
of single-phase of a particular V oxidation state is important for reaching optimal electrochemical performance of thin VOx films (VO2 or V2O5) grown by APCVD; the obtained V2O5 layers are electrochromic.[i]
[i] D. Vernardou, P. Paterakis, H. Drosos, E. Spanakis, I.M. Povey, M.E. Pemble, E. Koudoumas, N. Katsarakis, Solar Energy Materials and Solar Cells, 2011, Vol. 95, Iss. 10, p.2842-2847, « A study of the electrochemical performance of vanadium oxide thin films grown by atmospheric pressure chemical vapour deposition », https://doi.org/10.1016/j.solmat.2011.05.046 , https://www.sciencedirect.com/science/article/pii/S0927024811003217
Vanadium tetrachloride (VCl4) was applied as doping precursor for growing vanadium (V)-doped GaAs (GaAs:V) layers by MOCVD.
Different V-doping levels (1017–1019 cm−3) were achieved by annealing in an AsH3–H2 gas mixture up to 750-850 °C for 30 min. The Hall effect, deep level transient spectroscopy and PL measurements were applied for the study of effect of thermal treatments
on GaAs:V electrical and optical properties. Thermal conversion from the n- to p-type of weakly V-doped GaAs occurred upon annealing at 750 °C; however, the conductivity remained n-type for highly V-doped materials. However, annealing at 850 °C
induced convert from n- to p-type for all V-doped GaAs samples. The important role of Ga vacancies and a possible V accumulation at the surface in the case of thermal conversion was revealed by comparing the PL spectra for films annealed under different conditions. [i]
[i] A. Bchetnia, A. Rebey, J.L. Fave, J.C. Bourgoin, B. El Jani, J. Phys. D: Appl. Phys. 2006, 39 1337, « Effects of thermal annealing on n-type GaAs:V grown by MOCVD », doi:10.1088/0022-3727/39/7/002, http://iopscience.iop.org/0022-3727/39/7/002