Rubidium sulfide

Rubidium sulfide is an inorganic compound and a salt with the chemical formula Rb2S. It is a white solid with similar properties to other alkali metal sulfides.

Production
By dissolving hydrogen sulfide into rubidium hydroxide solution, it will produce rubidium bisulfide, followed by rubidium sulfide.


 * $$\mathrm{ RbOH + H_2S \longrightarrow RbHS + H_2O }$$
 * $$\mathrm{ RbHS + RbOH \longrightarrow Rb_2S + H_2O }$$

Physical properties
Rubidium sulfide has a cubic crystal similar to lithium sulfide, sodium sulfide and potassium sulfide, known as the anti-fluorite structure. Their space groups are $$Fm\bar{3}m$$. Rubidium sulfide has a crystal lattice unit cell dimension of = 765.0 pm.

Chemical properties
Rubidium sulfide reacts with sulfur in hydrogen gas to form rubidium pentasulfide, Rb2S5.