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BaC 4 O4 4 — Ein kristallwasserfreies Erdalkaliquadratat mit dreidimensionaler Gerüststruktur und schichtartiger Trennung von Kationen und Anionen
Author(s) -
Köferstein Roberto,
Robl Christian
Publication year - 2003
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.200390061
Subject(s) - crystallography , tetragonal crystal system , chemistry , aqueous solution , prism , crystallization , crystal structure , stereochemistry , physics , optics , organic chemistry
BaC 4 O4 4 — An Alkaline‐Earth Squarate Free from Water of Crystallization with Three‐dimensional Framework Structure Featuring a Layer‐like Separation of Cations and Anions Colourless single crystals of BaC 4 O 4 have been obtained from aqueous solution at 80 °C. BaC 4 O 4 is stable in air up to 490 °C. BaCO 3 is formed by further increase of temperature. BaC 4 O 4 crystallizes in the tetragonal space group I4/mcm (nr. 140) with a=635.95(5), c=1240.77(13) pm, Z=4. Ba 2+ is coordinated by eight oxygen atoms of the squarate dianions; Ba—O 276.1(1) pm. The coordination polyhedron is a distorted, square anti‐prism. The squarate dianions occupy crystallographic mirror planes and posses approximately 4/mmm symmetry; C—C 145.7(5) and 146.5(5) pm, C—O 125.9(3) pm. A layer‐like separation between the cations and anions exists with respect to the [001] direction.