Absorption Spectra of Tetrahedral Co(II) in Single Crystals of [N(CH3)4]2[CoX4] (X=Cl,Br)

The optical absorption spectra of single crystals of [N(CH3)4]2[CoCl4] and [N(CH3)4]2[CoBr4] have been measured over the range of 4000–33000 cm−1 at the temperature of liquid nitrogen and at room temperature. The spectra have been analyzed using the crystal-field theory which includes spin-orbit coupling. Some discussion of the Racah parameter B and of the 4T1(4F) and 4T1(4P) states is presented.