The 3D rhodium-gallium polyanion [Rh2Ga8] is the main building part of the isotypic compounds EuTM2Ga8 (TM = Co, Rh, Ir; CeFe2Al8 type of crystal structure). Europium species show two types of interaction: ionic through the charge transfer and covalent by the electrons of the fifth shell. In agreement with the bonding analysis for EuRh2Ga8, magnetic susceptibility and X-ray absorption spectra confirm mainly the 4f(7) with a small admixture of 4f(6) electronic configuration of europium.