Laser Raman spectra of uranyl tetrachloride complexes [K2UO2Cl4, Rb2UO2Cl4, (Cs2UO2Cl4, (NH4)2UO2Cl4] have been measured in the region from 3500 to 10 cm−1. Vibrational assignments as well as normal coordinate analyses have been carried out with the assumption that all the complexes contain discrete (UO2Cl4)2- ions belonging to a point group D4h. To understand the nature of the uranyl bonds in the complexes, approximate π-bonding energies of such bonds have been estimated from the U—O stretching force constants. The reliability of the values obtained are discussed in detail on the basis of Mulliken's magic formula.
Ken Ohwada, "Laser Raman Spectra and Normal Coordinate Analysis of Some Uranyl Tetrachloride Complexes," Appl. Spectrosc. 34, 327-331 (1980)