Compression of Intermolecular Interactions in CS₂ Crystal

Carbon disulfide, CS₂, mp = 161.7 K, has been crystallized in situ in a diamond-anvil cell at 295 K and 1.26 GPa to give an orthorhombic Cmca structure. No phase transitions occur with further increasing pressure till the polymerization onset at 8 GPa. The crystal structure was determined by direct methods from single-crystal X-ray diffraction at 295 K at two pressure points:  1.8 and 3.7 GPa (esd’s in the lengths of CS bond 0.0001 nm). The molecular rearrangements have been rationalized by the close packing and equidistant S···S intermolecular interactions enforced by pressure. Although only slight lengthening of the covalent double CS bond has been observed till 3.7 GPa, the intensified intermolecular S···S and C···S interactions reveal the possible reaction pathways of pressure-induced polymerization of CS₂.