Information on the structure of the Np(V) coordination sphere in a ser
ies of hydroxo compounds of general formula MNpO2(OH)2.chi-H2O (I), M2
NpO2(OH)3.chi-H2O (II), and M3NpO2(OH)4.chi-H2O (III) is discussed on
the basis of a comparison of EPR spectra with IR and electronic-spectr
oscopy data.