Definition: A class of compounds of the type R-M, where a C atom is joined directly to any other element except H, C, N, O, F, Cl, Br, I, or At. (Grant & Hackh's Chemical Dictionary, 5th ed)
uranyl acetate [ uranaffin reactant,uranium acetate,uranyl acetate, dihydrate ] used after fixation in uranaffin procedure; RN given refers to parent cpd