Accession Number : AD0277740

Title :   A NUCLEAR MAGNETIC RESONANCE DETERMINATION OF THE HYDROGEN POSITIONS IN CA(OH)2

Corporate Author : ILLINOIS UNIV URBANA NOYES CHEMICAL LAB

Personal Author(s) : HENDERSON,D.M. ; GUTOWSKY,H.S.

Report Date : 02 APR 1962

Pagination or Media Count : 1

Abstract : A nuclear magnetic resonance (nmr) investigation was carried out on Ca(OH)2, a representative trioctahedral layer hydroxide, for which the proton magnetic resonance absorption was observed in crystal powders at liquid N and at room temperatures. The broadening of the nmr absorption line by interactions among the magnetic nuclei can be measured as the second moment. A particular structural model can be tested by calculating the second moment for it and comparing the result with the experimental value. Measurement of the second moment for a crystal powder enables one structural parameter to be determined. The Bernal-Megaw model was assumed for the position of H in trioctahedral layer hydroxides; the parameter dealt with was a separation distance p which determines the amount of pucker in the hexagonal nets of H nuclei. The experimental values obtained for the second moment are 12.4 ! 0.3 and 10.6 ! 0.7 sq gauss at liquid N and room temperatures, respectively. The hydrogen positions obtained from the low-temperature data are given by p = 0.62 ! 0.04A, which corresponds to Z sub H = 0.437 ! 0.004 and an O-H distance of 0.99 ! 0.02A. These results are compared with related x-ray, neutron diffraction and IR studies of Ca(OH)2 and an nmr study of brucite. (Author)

Descriptors :   CRYSTALS, DETERMINATION, MINERALS, NUCLEAR MAGNETIC RESONANCE

Distribution Statement : APPROVED FOR PUBLIC RELEASE