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Chalcocite (low) [Cu2S]
Structure Monoclinic
Space Group : P 21/c (No. 14)
a=15.2460 Å, b=11.8840 Å, c=13.4940 Å
a=90.00, b=116.35, g=90.00
Z=48
Atomic Positional Parameters
Reference
Evans HT Jr. (1971) Nature (London) Physical Science, 69, 232
Mineral Chemistry
Chalcocite, one of the common ore minerals of copper, is found in the supergene enriched zones of sulphide deposits, and is commercially valuable because of its high copper to sulphur ratio. The crystal structure of low chalcocite is based on a hexagonal close-packed sulphur arrangement. Although the copper arrangement is complex, most copper atoms have triangular coordination. A few copper atoms are tetrahedrally coordinated. Above 103oC, the copper ions in low-chalcocite disorder to form high-chalcocite, a much simpler structure. The structure of high-chalcocite is hexagonal with unit cell dimensions of a=3.96 Å and c=6.72 Å for 2[Cu2S].
The CHIME figure shows the unit cell of low-chalcocite, with the unit cell outlined in grey. Click on buttons below to alter CHIME figure
Cu1 0.8647 0.2496 0.2923
Cu2 0.6171 0.0733 0.6766
Cu3 0.6100 0.0906 0.1673
Cu4 0.3627 0.2392 0.0743
Cu5 0.1283 0.0858 0.9452
Cu6 0.1060 0.0789 0.4422
Cu7 0.9340 0.1228 0.9916
Cu8 0.9413 0.1413 0.5094
Cu9 0.7617 0.2505 0.4112
Cu10 0.4431 0.1488 0.9352
Cu11 0.4259 0.1235 0.4390
Cu12 0.2581 0.2355 0.8512
Cu13 0.8212 0.0360 0.6834
Cu14 0.7832 0.0623 0.1673
Cu15 0.0264 0.2044 0.7726
Cu16 0.5020 0.0800 0.2837
Cu17 0.3030 0.0434 0.6232
Cu18 0.3050 0.0431 0.1343
Cu19 0.5251 0.2085 0.7543
Cu20 0.9994 0.0854 0.2174
Cu21 0.6229 0.1043 0.9537
Cu22 0.7034 0.1939 0.5653
Cu23 0.2028 0.2082 0.1405
Cu24 0.1307 0.0963 0.6792
S1 0.9570 0.0847 0.8420
S2 0.9399 0.0774 0.3457
S3 0.7924 0.0827 0.5068
S4 0.7918 0.0830 0.0054
S5 0.4495 0.0873 0.6140
S6 0.4444 0.0721 0.0948
S7 0.3020 0.0776 0.7881
S8 0.2834 0.0817 0.2865
S9 0.6972 0.2482 0.7223
S10 0.5479 0.2244 0.4168
S11 0.1960 0.2384 0.4752
S12 0.0475 0.2323 0.1338