Intergrowths between djurleite (~Cu1.94S) and digenite (~Cu1.8S) and between djurleite and chalcocite (Cu2S) and the transformation between djurleite (dj) and chalcocite (cc) were studied using high-resolution transmission electron microscopy.

Pseudohexagonal twins are common in djurleite; crystal blocks are rotated relative to each other around [100], the normal of the close-packed layers, by multiples of 60°. Djurleite and digenite (dg) bands are intergrown, with (111)dg, parallel to (100)dj, thereby creating a cubic-hexagonal alternation in the sequence of close-packed layers. The typical orientational relationship between coexisting djurleite and chalcocite is where [001]cc is parallel to [100]dj, and [010]cc is parallel to one of the 〈010〉 or 〈012〉 directions of djurleite.

If both djurleite and chalcocite occur in a sample, chalcocite easily converts to djurleite under the electron beam through the rearrangement of Cu atoms. A similar electrochemical transformation probably takes place in Cu2S-CdS solar cells and is the reason for the instability ofchalcocite in such devices.

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