Mixed sodium nickel-manganese sulfates: Crystal structure relationships between hydrates and anhydrous salts

Thermal dehydration of the blödite phase Na2Ni1−xMnx(SO4)2·4H2O (0≤ x≤0.49) yields nickel-manganese sulfates Na2Ni1−xMnx(SO4)2 (0≤ x≤0.44) with a large monoclinic cell, while the alluaudite phase Na2+δMn2-δ/2(SO4)3 is obtained from the kröhnkite phase Na2Ni1−xMnx(SO4)2·2H2O (0.97≤x≤1.0).202