Ytterbium(II) sulfide

Ytterbium(II) sulfide is a binary inorganic compound of ytterbium and sulfur with the chemical formula YbS.

Synthesis
Synthesis of ytterbium(II) sulfide can be via a reaction of pure substances in an inert atmosphere:
 * Yb + S -> YbS

An alternative synthesis is by comproportionation of ytterbium(III) sulfide and ytterbium metal in vacuum at 1000–1100 °C:
 * Yb2S3 + Yb -> 3YbS

Physical properties
Ytterbium(II) sulfide forms black crystals of cubic symmetry, space group Fm3m, cell parameter a = 0.5658 nm, Z = 4.

Ytterbium(II) sulfide demonstrates semiconductor behavior.