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Synthesis and Characterization of the Synthetic Minerals Villyaellenite and Sarkinite, Mn 5 (AsO 4 ) 2 (HAsO 4 ) 2 · 4H 2 O and Mn 2 (AsO 4 )(OH)
Author(s) -
Stock N.,
Stucky G. D.,
Cheetham A. K.
Publication year - 2002
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/1521-3749(200202)628:2<357::aid-zaac357>3.0.co;2-v
Subject(s) - monoclinic crystal system , manganese , impurity , hydrothermal circulation , crystallography , crystal structure , single crystal , chemistry , hydrothermal synthesis , materials science , geology , organic chemistry , seismology
Using hydrothermal methods, two manganese arsenates have been synthesized and characterized by single crystal X‐ray diffraction. The products Mn 5 (AsO 4 ) 2 (HAsO 4 ) 2 ?4H 2 O ( 1 ) and Mn 2 AsO 4 (OH) ( 2 ), the Mn end‐members of the minerals villyaellenite and sarkinite, respectively, have been obtained (crystal data 1 : monoclinic, C2/c, a = 18.109(4), b = 9.332(2), c = 9.809(2) Å, β = 96.172(4)?, Z = 4; 2 : monoclinic, P2 1 /c, a = 10.219(2), b = 13.613(2), c = 12.780(2) Å, β = 108.834(2)?, Z = 16). In both compounds a three‐dimensional framework of edge‐sharing MnO polyhedra is observed. Based on the availability of the all Mn2containing form of villyaellenite ( 1 ), the ordering scheme of the impurity cations of the natural samples could be confirmed. Magnetic susceptibility measurements of 1 indicate the presence of high‐spin Mn 2+ ions. The comparison of the data on sarkinite ( 2 ) with the data obtained from the natural sample indicates that the mineral has either a very high Mn content, or an absence of impurity cation ordering.