TY - JOUR

T1 - Reversible hydration/dehydration and thermal expansion of euchlorine, ideally KNaCu 3 O(SO 4 ) 3.

AU - Siidra, O.I.

AU - Borisov, A.S.

AU - Lukina, E.A.

AU - Nekrasova, D.O.

AU - Platonova, N.V.

PY - 2019

Y1 - 2019

N2 - Anhydrous alkali copper sulfates constitute the most abundant group of mineral species from the Second Scoria Cone of the Great Tolbachik Fissure Eruption (1975–1976), a location being renowned for its great mineral diversity. Euchlorine, ideally KNaCu 3 O(SO 4 ) 3 , is the prevalent mineral in the hot sulfate-rich zones of the fumaroles. In this work, its thermal expansion and hydration/dehydration behavior have been studied. The results of a structure refinement from new single-crystal diffraction data are also reported, and a description of the structure based on anion-centered coordination polyhedra is given. The strongly anisotropic character of the thermal expansion of euchlorine remains essentially unchanged up to its decomposition. The strongest α 11 expansion is observed approximately perpendicular to the alkali interlayer of the structure, whereas the minimal α 22 and α 33 thermal expansion coefficients are parallel to the

AB - Anhydrous alkali copper sulfates constitute the most abundant group of mineral species from the Second Scoria Cone of the Great Tolbachik Fissure Eruption (1975–1976), a location being renowned for its great mineral diversity. Euchlorine, ideally KNaCu 3 O(SO 4 ) 3 , is the prevalent mineral in the hot sulfate-rich zones of the fumaroles. In this work, its thermal expansion and hydration/dehydration behavior have been studied. The results of a structure refinement from new single-crystal diffraction data are also reported, and a description of the structure based on anion-centered coordination polyhedra is given. The strongly anisotropic character of the thermal expansion of euchlorine remains essentially unchanged up to its decomposition. The strongest α 11 expansion is observed approximately perpendicular to the alkali interlayer of the structure, whereas the minimal α 22 and α 33 thermal expansion coefficients are parallel to the

M3 - Article

VL - 46

SP - 403

EP - 416

JO - Physics and Chemistry of Minerals

JF - Physics and Chemistry of Minerals

SN - 0342-1791

IS - 4

ER -