INFRARED SPECTRUM IN POLARIZED LIGHT OF CH2BR2 AND CD2BR2 DETERMINATION OF CRYSTAL STRUCTURE

The infrared spectra of crystalline CH2Br2 and CD2Br2 were measured at liquid-nitrogen temperature, between 4000 and 200 cm−1. Splitting of the normal modes was observed for several fundamentals. These data, together with polarization measurements on polycrystalline oriented films, were used to study the crystal structure of CH2Br2. The technique of mixed crystals was used to prove the nature of the observed crystal splittings. The data accumulated on this molecule are consistent with a monoclinic [formula omitted] unit cell or with a triclinic [formula omitted] cell with two sets of sites. The differences are discussed in terms of close packing. © 1968, American Institute of Physics. All rights reserved.