Vanadium(III) fluoride is the chemical compound with the formula VF3. This yellow-green, refractory solid is obtained in a two-step procedure from V2O3.[1] Similar to other transition-metal fluorides (such as MnF2), it exhibits magnetic ordering at low temperatures (e.g. V2F6.4H2O orders below 12 K[2]).
The first step entails conversion to the hexafluorovanadate(III) salt using ammonium bifluoride:
V2O3 + 6 (NH4)HF2 → 2 (NH4)3VF6 + 3 H2O
In the second step, the hexafluorovanadate is thermally decomposed.
(NH4)3VF6 → 3 NH3 + 3 HF + VF3
The thermal decomposition of ammonium salts is a relatively common method for the preparation of inorganic solids.
VF3 can also be prepared by treatment of V2O3 with HF.VF3 is a crystalline solid with 6 coordinate vanadium atoms with bridging fluorine atoms. The magnetic moment indicates the presence of two unpaired electrons.