Magnetic and Spectroscopic Properties of the Linear Complex [NiO2]2– in K2[NiO2] and Rb2[NiO2]

IR and VIS spectra of Rb₂NiO₂] have been recorded between 25–20000 cm^–1. The d‐d transitions can be assigned on the basis of a ligand field calculation for the linear NiO₂]^2– complex with a ³π_g ground state. Furthermore the parameter set for the proposed assignment has been used to calculate the magnetic properties of these anions in excellent agreement with the measured susceptibility data of the isotypic compound, K₂NiO₂].