The Crystal Structure of Klyuchevskite, K3Cu3(Fe,Al)O2(SO4)4, a New Mineral from Kamchatka Volcanic Sublimates

M. G. Gorskaya*, S. K. Filatov*, I. V. Rozhdestvenskaya† and L. P. Vergasova‡
State University Russia
* LPO ‘Burevestnik’ Russia
† St.-Petersburg Institute of Volcanology, Academy of Sciences, Russia
‡ Petropavlovsk-Kamchatsky, Russia

Abstract: The crystal structure of klyuchevskite, K3Cu3(Fe3+,Al)O2(SO4)4, was determined in space group 12 using the total of 715 independent reflections up to R 0.12. Klyuchevskite is a structural analogue of piypite (caratiite) K4Cu4O2(SO4)4MeCl with the substitution K+ + Cu2+ → (Fe3+,Al) + MeCl. Compared to piypite, the ordering of Cu2+ and Fe3+ cations in the klyuchevskite structure results in the distortion of the unit cell and in lowering the symmetry of the chains to 1.

This brings about a more compact packing of the chains. The chain-like arrangement of the structure determines physical properties of the mineral, its acicular habit, perfect cleavage, strong anisotropy of optical properties and orientation of optical indicatrix.

Keywords: klyuchevskite • crystal structure • piypite • Tolbachik volcano • Russia

Mineralogical Magazine; September 1992 v. 56; no. 384; p. 411-416; DOI: 10.1180/minmag.1992.056.384.14
© 1992, The Mineralogical Society
Mineralogical Society (www.minersoc.org)