A new hydrate of magnesium carbonate, MgCO3·6H2O

During investigations of the formation of hydrated magnesium carbonates, a sample of the previously unknown magnesium carbonate hexahydrate (MgCO 3 ·6H 2 O) was synthesized in an aqueous solution at 273.15 K. The crystal structure consists of edge-linked isolated pairs of Mg(CO 3 )(H 2 O) 4 octahedra and noncoordinating water molecules, and exhibits similarities to NiCO 3 ·5.5H 2 O (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 (MgCO 3 ·3H 2 O) at room temperature.