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K 2 [(UO 2 )As 2 O 7 ] – the First Uranium Polyarsenate
Author(s) -
Alekseev Evgeny V.,
Krivovichev Sergey V.,
Depmeier Wulf
Publication year - 2007
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/zaac.200700020
Subject(s) - orthorhombic crystal system , uranyl , octahedron , crystallography , silicate , uranium , crystal structure , melilite , materials science , chemistry , inorganic chemistry , metallurgy , organic chemistry , spinel
Yellowish crystals of K 2 [(UO 2 )As 2 O 7 ] ( 1 ) have been synthesized by solid‐state reactions method. The structure of 1 [orthorhombic, Pmmn , a = 12.601(2), b = 13.242(2), c = 5.621(1) Å, V = 937.9(3) Å 3 , Z = 4] has been solved by direct methods and refined to R 1 = 0.049, wR 2 = 0.1060 for 1059 observed reflections. The structure of 1 is based upon [(UO 2 )As 2 O 7 ] 2− sheets formed by corner sharing between [UO 6 ] 6− distorted octahedra and [As 2 O 7 ] 4− polyarsenate groups. The K + cations are either in eightfold or tenfold coordination and are located between the sheets. The topology of the uranyl arsenate sheet is related to silicate minerals of the melilite group and related synthetic silicate, aluminate and germanate compounds.