Referenza:
▪ Khanin, D.A. & Pekov, I.V. (2018): Minerals with Brackebuschite-Like Structures: A Novel Solid Solution System Involving Cr6+ and V5+. Geology of Ore Deposits, 59, 642-651.
Abstract:
A novel complex continuous system of solid solutions involving vauquelinite Pb2Cu(CrO4)(PO4)(OH), bushmakinite Pb2Al(VO4)(PO4)(OH), ferribushmakinite Pb2Fe3+(VO4)(PO4)(OH), and a phase with the endmember formula Pb2Cu(VO4)(PO4)(H2O) or Pb2Cu(VO4)(РО3ОН)(ОН) is studied based on samples from the oxidation zone of the Berezovskoe, Trebiat, and Pervomaisko-Zverevsky deposits in the Urals, Russia. This is the first natural system in which chromate and vanadate anions show a wide range of substitutions and the most extensive solid solution system involving (CrO4)2– found in nature. The major couple substitution is Cr6+ + Cu2+ ↔ V5+ + M3+, where M = Fe, Al. The correlation coefficients calculated from 125 point analyses are: 0.96 between V and (Fe + Al), 0.96 between Cr and (Cu + Zn), –0.96 between V and (Cu + Zn), –0.97 between Cr and (Fe + Al), and –0.97 between (Fe + Al) and (Cu + Zn). The substitutions V5+ ↔ Cr6+ (correlation coefficient –0.98) and to a lesser extent P5+ ↔ As5+ (correlation coefficient –0.86) occur at two types of tetrahedral sites, whereas the metal–nonmetal/metalloid substitutions, i.e., V or Cr for P or As, are minor. The substitution Fe3+ ↔ Al3+ is also negligible in this solid solution system.
Minerals with brackebuschite-like structures: A novel solid solution system involving Cr6+ and V5+
- Marco E. Ciriotti
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Minerals with brackebuschite-like structures: A novel solid solution system involving Cr6+ and V5+
Marco E. Ciriotti
«Things are interesting only in so far as they relate themselves to other things»
«Things are interesting only in so far as they relate themselves to other things»
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