Atomic Positional Parameters
Pt 2c 0.0000 0.5000 0.0000
S  2e 0.0000 0.0000 0.2500

References
FA Bannister and MH Hey (1932) Mineralogical Magazine, 23, 188

F Groenvold, H Haraldsen and A Kjekshus (1960) Acta Chemica Scandinavica, 14, 1879

Mineral Chemistry
Cooperite is a rare platinum-bearing sulphide mineral. Platinum is also found in nature as the native metal, as platiniridium, a platinum-iridium alloy, and as sperrylite (PtAs₂) which has the pyrite structure. In cooperite, platinum is coordinated by four sulphurs in a square planar arrangement. Sulphurs are tetrahedrally coordinated by four platinum ions.

The Chime figure shows platinum atoms coloured grey and sulphurs yellow. Note the square planar coordination of the platinum ions.