Ytterbium(II) bromide

Ytterbium(II) bromide is an inorganic compound with the chemical formula YbBr2.

Preparation
Ytterbium(II) bromide can be produced by the reduction reaction of ytterbium(III) bromide and hydrogen at 500~600 °C:


 * 2 YbBr3 + H2 -> 2 YbBr2 + 2 HBr

The ammonia compound can be obtained by reacting metallic ytterbium and ammonium bromide in liquid ammonia at −78 °C. The ammonia compound can be decomposed in high vacuum at 200 °C to obtain ytterbium(II) bromide:


 * Yb + 2 NH4Br -> YbBr_2 + 2 NH3 + H2

Ytterbium(II) bromide can also be prepared by vacuum reduction of metallic ytterbium at 960 °C:


 * Yb + 2 YbBr3 -> 3 YbBr2

Properties
Ytterbium(II) bromide is a light yellow solid and is highly hygroscopic. It can only be stored in an inert atmosphere or high vacuum. It is unstable in air or moisture and rapidly converts to the oxybromide and releases hydrogen gas. Ytterbium(II) bromide belongs to the orthorhombic crystal system, with SrI2 structure and space group Pbca, or CaCl2 structure and space group Pnnm. Its unit cell parameters are a=6.63 Å, b=6.93 Å, c=4.47Å.