Investigation into the dehydration of selenate doped Na2M(SO4)2·2H2O (M = Mn, Fe, Co and Ni): Stabilisation of the high Na content alluaudite phases Na3M1.5(SO4)3-1.5x(SeO4)1.5x (M = Mn, Co and Ni) through selenate incorporation

The refined crystal structure of alluaudite-type Na3Co1.5(SO4)1.5(SeO4)1.5 (Tetrahedra = S/SeO4; Co (and mixed Co/Na site) at the centre of octahedra, Spheres = Na)243