Spectrochemical Study of Microscopic Crystals. VII. Absorption Spectra of Trans-dihalogeno-bis (ethylenediamine)-cobalt (III) Complexes

Abstract
Dichroism of the crystals of trans-[Co(en)2Cl2]ClO4, [Co(en)2Cl2]Cl·HCl·2H2O and [Co(en)2Br2]Br·HBr·2H2O have been quantitatively determined by Tsuchida-Kobayashi’s microscopic method in the visible and ultraviolet regions. As to the dichroism of the trans-dihalogeno-complexes, the following relations have been induced. The first band splits itself into two component absorptions. One at the longer wave-length is polarized in the X-Co-X direction, and the other at the shorter wave-length is polarized in the Co-en plane. For the third and specific bands, the X-Co-X-absorption is bathochromic to the Co-en-absorption. On the basis of the above results, absorption spectra of several praseo-complexes in solution have been discussed.