The infrared pleochroism of lawsonite:
The orientation of the water and hydroxide groups

Teodore C. Labotka, George R. Rossman
Divisionof Geological and Planetary Sciences
California Institute of Technology
Pasadena, CA  91109


Polarized infrared absorption spectra of thin single crystals of lawsonite, CaAl2(OH)2Si2O7,H2O, have been measured at room temperature and near 78 K. These data suggest a structural model in which the hydrogen atome of both OH and H2O lie in planes parallel to (001). THe polarization data demand that the order ofthe energies of the symetric and antiymmetric stretch of the crystallograpnically ordered water in lawsonite be reversed frm that of liquid water.

Lawsonite spectrum
Infrared spectrum of lawsonite in the water and OH region at a temperature near 78 K with E\\a  and E\\b.

last updated: 27-Jul-2023