The crystal structure of covellite has been refined using powder photographs with a Debye camera. Oftedal's structural hypothesis has been confirmed and least squares refinement with 48 reflections yielded a reliability index of 10,4%. Small variations in the atomic positional parameters and fairly large ones in the thermal parameters were observed. The thermal parameter related to the copper atom in triangular coordination was found to be highly anisotropic. The presence of disulfide groups has been evidenced and consequently a new formula for covellite has been proposed: Cu4 (S2)2 • 2CuS.
Referenze Bibliografiche
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Con il contributo del Ministero per i Beni e le Attività Culturali