A CRYSTALLOGRAPHIC STUDY OF MAGNESIUM AMMONIUM SULFATE HEXAHYDRATE

摘要

Three-dimensional x-ray diffraction data were taken with the General Electric goniostat. The structure, including hydrogen atoms, was determined by Fourier and least-squares methods. The mag¬nesium atom is surrounded by an octahedron of water molecules, each forming two hydrogen bonds to oxygen atoms of the sulfate ions. Three hydrogen atoms of each ammonium ion are bonded to sulfate oxygen atoms, but the fourth is equidistant from two sulfate oxygen atoms with the geometry which previous authors have called a "bifurcated hydrogen bond". Average interatomic distances (uncorrected for thermal motion) are: Mg-0 = 2.07, S-0 = 1.47, 0-0 (hydrogen bonded) = 2.77, N-0 (hydrogen bonded) = 2.90, and N-0 (bifurcated bond) = 3.08 A. The average S-0 bond length after correction for thermal motion is l.h9 A.