TY - JOUR

T1 - Redefinition of Lemanskiite

T2 - New Mineralogical Data, Crystal Structure, and Revised Formula NaCaCu 5 (AsO 4 ) 4 Cl · 3H 2 O

AU - Zubkova, N. V.

AU - Pekov, I. V.

AU - Chukanov, N. V.

AU - Kasatkin, A. V.

AU - Ksenofontov, D. A.

AU - Yapaskurt, V. O.

AU - Britvin, S. N.

AU - Pushcharovsky, D. Yu

PY - 2018/12/1

Y1 - 2018/12/1

N2 - 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 NaCaCu 5 (AsO 4 ) 4 Cl · 5H 2 O and differs from the latter by a lower H 2 O content. The studied sample was from the oxidation zone of the Perseverancia deposit, Guanako, Antofagasta, Chile. It empirical formula is Na 0.98 (Ca 0.98 Sr 0.03 )Σ 1.01 Cu 5.07 As 3.97 O 15.97 Cl 1.03 · 3H 2 O; the idealized formula is NaCaCu5(AsO4)4Cl · 3H2O. The mineral is monoclinic, P 2 1/m, a = 9.250(2), b = 10.0058(10), с = 10.0412(17) Å, β = 97.37(3)°, V = 921.7(3) Å 3 , 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 AsO 4 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.

AB - 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 NaCaCu 5 (AsO 4 ) 4 Cl · 5H 2 O and differs from the latter by a lower H 2 O content. The studied sample was from the oxidation zone of the Perseverancia deposit, Guanako, Antofagasta, Chile. It empirical formula is Na 0.98 (Ca 0.98 Sr 0.03 )Σ 1.01 Cu 5.07 As 3.97 O 15.97 Cl 1.03 · 3H 2 O; the idealized formula is NaCaCu5(AsO4)4Cl · 3H2O. The mineral is monoclinic, P 2 1/m, a = 9.250(2), b = 10.0058(10), с = 10.0412(17) Å, β = 97.37(3)°, V = 921.7(3) Å 3 , 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 AsO 4 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.

KW - arsenate

KW - Chile

KW - crystal structure

KW - lavendulan

KW - lavendulan group

KW - lemanskiite

KW - oxidation zone

KW - Perseverancia mine

UR - http://www.scopus.com/inward/record.url?scp=85062454296&partnerID=8YFLogxK

U2 - 10.1134/S1075701518070115

DO - 10.1134/S1075701518070115

M3 - Article

AN - SCOPUS:85062454296

VL - 60

SP - 594

EP - 606

JO - Geology of Ore Deposits

JF - Geology of Ore Deposits

SN - 1075-7015

IS - 7

ER -