Barium tetrasulfide monohydrate

Barium also forms several other sulfides. Among them are Barium hydrosulfide, Ba(SH)2 [25417-81-6] Barium disulfide, BaS2 [12230-99-8] Diharium trifulfide, Ba2Ss [53111-28-7] Barium trisulfide, BaSs [12231-01-5] Barium tetrasulfide monohydrate, BaS4 H20 [12248-67-8] Barium pentasulfide, BaSs [12448—68—9]. 

The crystals of barium tetrasulfide monohydrate, BaS4 H20, are orthorhombic, with four formula units in a cell of dimensions a = 9.67 A, b = 7.99 A, c = 7.81 A. The space group is Dt -P212l2. The unbranched, nonplanar tetrasulfide ions lie on twofold axes of symmetry, with only right-handed or only left-handed forms in each unit cell. 

The enantiomorphs of a nonplanar disulfide sometimes become separated in crystals. Thus, diphenyl disulfide (43) and probably also di-p-tolyl disulfide (43) crystallize in enantiomorphous space groups with only one enantiomorph per unit cell, and so do barium tetrasulfide monohydrate (1) and sodium tetrathionate dihydrate (101). The same applies, of course, to L-cystine and other optically active disulfides. 

The trans-tram forms occur in the crystals of cesium hexasulfide (5) and of (rans-dichloro-dien-cobalt(III) hexathionate monohydrate (107), and the ds-ds forms in the crystals of potassium barium hexathionate (102), these being the only compounds containing tetrasulfide groups for which structural data are available. 

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