Study the Structural and Optical Properties of Magnesium Sulphate Heptahydrate Single Crystal Grown by Solution Growth Method

Abstract

Single crystals with considerable dimensions were successfully grown by the natural evaporation method from aqueous solutions. Pure (MgSO4.7H2O), doped with Ni (Mg1-yNiySO4.7H2O where y= 0, 0.5,1,3 and 5% mol) and with changing the acidic medium of the solution (where pH=7, 5, 4, 3 and 2). The mass growth rate of all the grown crystals was investigated. X-ray powder diffraction measurement confirmed the emergence of the orthorhombic phase of MgSO4.7H2O and all patterns are agreed very well with the (JCPDS) file No. (36-0419). In the case of Ni-doped (MgSO4.7H2O) crystals, growth rate increased with dopant concentrations especially at (1 %mole) and the size of the largest crystal was found to be (41.20*13.34*11.23) mm3 at 1% Ni concentration and the parameters of the largest crystal were (a=11.861Å, b=11.981Å, c=6.852Å). The colour of dopant crystals changed from transparent, colourless to greenish. The size of the largest crystals of (MgSO4.7H2O) that grow in an acidic medium was found to be (62.21*5.38*6.19) mm3 at pH =5, and the parameters of the largest crystal were (a=11.871Å, b=11.993 Å, c=6.855 Å). All the grown crystals are well-faced, optically transparent, free defect, and good quality. The optical properties were studied by using UV-Vis analysis; all crystals have shown good absorption in the infrared and visible area of the spectrum. The characteristic peaks of Mg– O, OH, HOH and SO bond stretching or bending vibrations was revealed by FTIR spectroscopy.