Growth and Some Properties of Mixed Crystals of Non-Isostructural Series of Nickel and Cobalt Sulfates Hexahydrates

The dependence of the solubility of NixCo $$_{{1-x}}$$ SO4⋅6H2O (x = 0–1) on the composition of the solution at a temperature of 45°C has been obtained. It is found that heating leads to a shift of the point of invariant equilibrium of the tetragonal and monoclinic phases towards a higher cobalt concentration in the solution. A thermogravimetric study showed that the thermal stability of the crystal decreases with an increase in the Co content in it. The spectral characteristics of crystals of different compositions showed that the crystal under study can be used as a UV filter. The habit of a monoclinic NixCo $$_{{1-x}}$$ SO4⋅6H2O crystal, obtained from a solution of the NiSO4 : CoSO4 = 50 : 50 wt % composition, was determined.