Crystal structure study of a cobaltoan dolomite from Kolwezi, Democratic Republic of Congo.

ABSTRACT: A structural study has been undertaken on a cobaltoan dolomite, with chemical formula CaMg0.83Co0.17(CO3)2 (cal-cium magnesium cobalt dicarbonate), from Kolwezi, Democratic Republic of Congo. Pale-pink euhedral cobaltoan dolomite was associated with kolwezite [(Cu1.33Co0.67)(CO3)(OH)2] and cobaltoan malachite [(Cu,Co)2(CO3)(OH)2]. A crystal with a Co:Mg ratio of 1:5.6 (SEM/EDAX measurement), twinned on (11 -2 0) was used for crystal structural refinement. The refinement of the structural model of Reeder & Wenk [Am. Mineral. (1983 ▶), 68, 769-776; Ca at site 3a with site symmetry -3; Mg site at site 3b with site symmetry -3; C at site 6c with site symmetry 3; O at site 18f with site symmetry 1] showed that Co is totally incorporated in the Mg site, with refined occupancy Mg0.83Co0.17, which

SUBMITTER: Perchiazzi N 

PROVIDER: S-EPMC4350686 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature