Redefinition of Lemanskiite: New Mineralogical Data, Crystal Structure, and Revised Formula NaCaCu5(AsO4)4Cl · 3H2O
- Authors: Zubkova N.V.1, Pekov I.V.1, Chukanov N.V.2, Kasatkin A.V.3, Ksenofontov D.A.1, Yapaskurt V.O.1, Britvin S.N.4, Pushcharovsky D.Y.1
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Affiliations:
- Geological Faculty
- Institute of Problems of Chemical Physics
- Fersman Mineralogical Museum
- Institute of the Earth Sciences
- Issue: Vol 60, No 7 (2018)
- Pages: 594-606
- Section: New Minerals
- URL: https://journals.rcsi.science/1075-7015/article/view/215385
- DOI: https://doi.org/10.1134/S1075701518070115
- ID: 215385
Cite item
Abstract
The crystal structure of lemanskiite is determined for the first time (R = 0.019) and the mineral is redefined. Its chemical formula, crystal system, space group and unit-cell parameters are revised. The powder X-ray diffraction pattern of lemanskiite has been correctly indexed; the IR spectrum of an impurity-free sample has been obtained. It has been shown that the mineral is not a dimorph of lavendulan NaCaCu5(AsO4)4Cl · 5H2O and differs from the latter by a lower H2O content. The studied sample was from the oxidation zone of the Perseverancia deposit, Guanako, Antofagasta, Chile. It empirical formula is Na0.98(Ca0.98Sr0.03)Σ1.01Cu5.07As3.97O15.97Cl1.03 · 3H2O; the idealized formula is NaCaCu5(AsO4)4Cl · 3H2O. The mineral is monoclinic, P21/m, a = 9.250(2), b = 10.0058(10), с = 10.0412(17) Å, β = 97.37(3)°, V = 921.7(3) Å3, Z =2. Lemanskiite represents a new structure type in the lavendulan group. Its structure is based on heteropolyhedral layers composed of clusters consisting of four edge-shared distorted Cu-centered tetragonal pyramids joined with eight AsO4 tetrahedra, which are also linked with a Cu-centered plane squares not involved in the clusters. Interlayer edge-shared Na-centered trigonal prisms and Ca sevenfold polyhedra are linked with the heteropolyhedral layers from both sides.
About the authors
N. V. Zubkova
Geological Faculty
Author for correspondence.
Email: n.v.zubkova@gmail.com
Russian Federation, Moscow, 119991
I. V. Pekov
Geological Faculty
Email: n.v.zubkova@gmail.com
Russian Federation, Moscow, 119991
N. V. Chukanov
Institute of Problems of Chemical Physics
Email: n.v.zubkova@gmail.com
Russian Federation, Chernogolovka, Moscow oblast, 142432
A. V. Kasatkin
Fersman Mineralogical Museum
Email: n.v.zubkova@gmail.com
Russian Federation, Leninskii pr. 18-2, Moscow, 119071
D. A. Ksenofontov
Geological Faculty
Email: n.v.zubkova@gmail.com
Russian Federation, Moscow, 119991
V. O. Yapaskurt
Geological Faculty
Email: n.v.zubkova@gmail.com
Russian Federation, Moscow, 119991
S. N. Britvin
Institute of the Earth Sciences
Email: n.v.zubkova@gmail.com
Russian Federation, Universitetskaya nab. 7/9, St. Petersburg, 199034
D. Yu. Pushcharovsky
Geological Faculty
Email: n.v.zubkova@gmail.com
Russian Federation, Moscow, 119991