Samarium(II) fluoride

Samarium(II) fluoride is one of fluorides of samarium with a chemical formula SmF2. The compound crystalizes in the fluorite structure, and is significantly nonstoichiometric. Along with europium(II) fluoride and ytterbium(II) fluoride, it is one of three known rare earth difluorides, the rest are unstable.

Preparation
Samarium(II) fluoride can be prepared by using samarium or hydrogen gas to reduce samarium(III) fluoride:
 * $$\mathrm{2 \ SmF_3 + Sm \longrightarrow 3 \ SmF_2}$$


 * $$\mathrm{2 \ SmF_3 + H_2 \longrightarrow 2 \ SmF_2 + 2 \ HF}$$

Properties
Samarium(II) fluoride is a purple to black solid. This is present in the crystal structure of the cubic calcium fluoride type (space group Fm$\overline{3}$m; No. 225 with a = 587.7 pm).