Crystal Growth and Electro-optic Effect of Some Double Sulfates with the Langbeinite Structure

Abstract
Single crystals of several isomorphs of the mineral langbeinite, K2Mg2(SO4)3, space group T4, were prepared from aqueous solutions and from the melt. The electro‐optic powers, n03r41 of (NH4)2Mn2(SO4)3, K2Mn2(SO4)3, Rb2Mn2(SO4)3, Tl2Mn2(SO4)3 and K2Ni2(SO4)3 were found respectively to be 0.7, 8.6, 7.7, 12.4, and 4.9×10−10 cm/V. Refractive indices and dielectric constants were also measured. By analysis of the observed data it was found possible to partially resolve the over‐all electro‐optic effect into single ion contributions.