Crystal growth and crystal structure of magnesium oxysulfate 2MgSO 4·Mg(OH) 2·2H 2O

Abstract

The crystal of magnesium oxysulfate hydrate 2MgSO 4·Mg(OH) 2·2H 2O was synthesized in MgSO 4 and NaOH solutions at 160 °C for 21 days and its structure has been determined to be orthorhombic system space group Pbcm with cell data: a=7.177(1) Å, b=9.804(2) Å, c=12.775(2) Å, β=90°, and Z=4; Dc=2.476 g cm −3, μ=0.869 mm −1, F(000)=680. The structure was solved by full-matrix least-squares on methods and refined to R=0.0371, wR=0.0724 using 1036 independent reflections measured with a X-ray diffraction technology. The structure consists of straight chains of face-sharing of which Mg 2+ is at their centers. The Mg atom coordinated around O atom of SO 4 2− in another layer to form a multi-layer structure crystal. The thermal analytical curve of this compound was recorded and its decomposition mechanism was discussed.