Ammonium nickel sulfate hexahydrate crystal: a new ultraviolet light filter

Abstract

We propounded and grew a new crystal material of ammonium nickel sulfate hexahydrate (ANSH) for an ultraviolet light filter. The crystal structure of ANSH was solved by x-ray diffraction method and the empirical formula of the title compound is (NH4)2Ni(SO4)2⋅6H2O. The ANSH crystal belongs to the monoclinic space group P21/C, a = 6.2351 Å, b = 12.451(3) Å, c = 9.1798(18) Å, β = 106.88(3)°, v = 681.9(2) Å3, z = 2 and Dc = 1.924 g cm−3. The deep-green ANSH single crystal with a dimension of 20.5×28×15 mm3 has been grown by the cooling solution method. Thermo-gravimetry analysis showed that the dehydration temperature of the ANSH crystal is above 96.06°C, which is much higher than that of commercially available nickel sulfate hexahydrate (NSH) crystals. The optical transmission character of the ANSH crystal is discontinuous in the range from ultraviolet (UV) to near IR wavelengths, and has several transmission peaks at 250 nm, 500 nm, 875 nm and 1425 nm, respectively. The UV transmission peak (250 nm) especially has high transmission efficiency and a narrow spectrum band-width. The relationship between the structure and the optical transmission property is further discussed.