High-Pressure Structural Evolution of Disordered Polymeric CS₂

Carbon disulfide is an archetypal double-bonded molecule belonging to the class of group IV–group VI, AB2 compounds. It widely believed that, upon compression several GPa at room temperature and above, a polymeric chain type (−(C═S)–S−)n, named Bridgman’s black polymer, will form. By combining optical spectroscopy synchrotron X-ray diffraction data with ab initio simulations, we demonstrate that structure this polymer different. Solid molecular CS2 polymerizes ∼10–11 GPa. The disordered consists mixture 3-fold (C3) 4-fold (C4) coordinated carbon atoms some C═C double bonds. C4/C3 ratio continuously increases further 40 Upon decompression, structural changes are partially reverted, while sample also undergoes partial disproportionation. Our work uncovers nontrivial high-pressure evolution in one simplest systems exhibiting as well phases.