ORIENTATIONAL DISORDER OF SULFATE IONS IN THE CRYSTAL STRUCTURE OF NH4Al0.43Fe0.57(SO4)2·12H2O
V. Kh. Sabirov
Kazakh Engineering and Pedagogical University of Nations Friendship, Shymkent, Republic of Kazakhstan
Keywords: квасцы, твердые растворы, запрещенные рентгеновские отражения, максимальные подгруппы, ориентационный беспорядок, alum, solid solutions, forbidden X-ray reflections, maximal subgroups, orientational disorder
Abstract
The crystal structure of the solid solution of alum NH4Al0.43Fe0.57(SO4)2×12H2O (I) is studied in the space group Ра3(-) and its maximal subgroups R3(-), P1(-), and P1. In centrosymmetric space groups sulfate ions occupy one of two opposite orientations, and in the triclinic group P1 four of eight tetrahedra have the same orientation. The second harmonic generation is observed when a train of chirped optical pulses of ytterbium diode pumped solid state laser passes through the crystal of I.
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