Thulium(III) fluoride
# Thulium(III) fluoride

Thullium(III) fluoride is an inorganic compound with the chemical formula $TmF_3.$

## Production

It can be produced by reacting thulium(III) sulfide and hydrofluoric acid, followed by thermal decomposition:

    3 $Tm_2S_3$ + 20 HF + (2 + $2x)H_2O$ → 2 $(H_3O)Tm_3F_{10}·xH_2O↓$ + 9 $H_2S↑$ (x=1.7)
    $(H_3O)Tm_3F_{10}$ → 3 $TmF_3$ + HF↑ + $H_2O↑$

Thulium(III) oxide reacts with fluorinating agents such as hydrogen fluoride, nitrogen trifluoride xenon difluoride to create thullium(III) fluoride as well, although the reaction with nitrogen trifluoride is incomplete and produces a mixture of TmOF and $TmF_3.$

