Spectrochemical Study of Microscopic Crystals. XIII. The Structure of Wolffram’s Red Salt, Pt(NH2·C2H5)4Cl3·2H3O and a Related Compound

Abstract

Abstract Polarized absorption spectra of Wolffram’s red salt, Pt(EA)4Cl3·2H2O, and a related compound, Pt(EA)4Br3·2H2O, EA being ethylamine, have been determined by Tsuchida-Kobayashi’s microscopic method in the regions covering from 2400 to 7500 Å. Both the compounds, which are supposed to be formulated by [Pt(EA)4][Pt(EA)4X2]X4·4H2O, have been found to show an absorption band that has not been observed with either of the components alone. Moreover, this band is strongly polarized along the needle axis. These relationships may be understood on the assumption that the crystals of these compounds involve infinite chains of ---X—PtIV—X---PtII---X—PtIV—X--- along the needle axis, X being chlorine or bromine. The new absorption at the longer wavelength may be considered as a charge transfer band along the infinite chains as assumed above.