A new hydrate of magnesium carbonate, MgCO3·6H2O

Acta Crystallogr C Struct Chem. 2020 Mar 1;76(Pt 3):244-249. doi: 10.1107/S2053229620001540. Epub 2020 Feb 13.

Abstract

During investigations of the formation of hydrated magnesium carbonates, a sample of the previously unknown magnesium carbonate hexahydrate (MgCO3·6H2O) was synthesized in an aqueous solution at 273.15 K. The crystal structure consists of edge-linked isolated pairs of Mg(CO3)(H2O)4 octahedra and noncoordinating water molecules, and exhibits similarities to NiCO3·5.5H2O (hellyerite). The recorded X-ray diffraction pattern and the Raman spectra confirmed the formation of a new phase and its transformation to magnesium carbonate trihydrate (MgCO3·3H2O) at room temperature.

Keywords: Raman spectroscopy; carbonate; crystal structure; low-temperature hydrate; magnesium.