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The alluaudite-like arsenate NaCaMg(3)(AsO(4))(3)
Anissa Haj Abdallah1, Amor Haddad
1Laboratoire de Matériaux et Cristallochime, Institut Supérieur des Sciences Appliquées et Technologie de Mahdia, Avenue El Mourouj, Sidi Messoud 5111 Hiboun, Mahdia, Tunisia.
Abstract:
The title compound, sodium calcium trimagnesium tris-(arsenate), an alluaudite-like arsenate, was prepared by solid-state reaction at high temperature. The structure is built up from edge-sharing MgO(6) octa-hedra in chains associated with the AsO(4) arsenate groups. The three-dimensional network leads to two different tunnels occupied statistically by Na(+) and Ca(2+). One As and one Mg atom lie on twofold rotation axes; one Na and one Ca are disordered over two sites with occupancies of 0.7 and 0.3 and these sites lie on a twofold rotation axis and an inversion centre, respectively.
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