Potassium Nickel Magnesium Sulphate Hexahydrate (KMGNSH) crystals have successfully grown by using traditional slow evaporation method. The empirical formula of KMGNSH is K2Mg0.2Ni0.8 (SO4)2.6H2O with formula weight 438.352. KMGNSH crystal revealed monoclinic space group P2(1)/c, a=6.111(4) Å, b=12.15 (9) Å, c=8.97 (7) Å, α=γ=90°, β=105.122(2)°, V=643(1)Å3, Z=2, Dc=2.1634g/cm3 with deep green color. IR confirms that there is strong interaction between free water molecules. The thermal analysis indicates that the water molecules are present in the KMGNSH crystals. The transmission spectrometry of KMGNSH in the range from UV to near IR wavelengths is reported.
