Anhydrous copper butyrate, [CH3(CH2)2COO]2Cu, is triclinic witha = 9.004 + 0.005, b = 11.736 + 0.005, c=5"162+0"005/~,, 6t=94.7+0.5, fl=71.3+0.5, and y=95.2+0.5 . The space group is P] w~-h each cell containing one dimer made up of two of the above formula units. Two of the hydrocarbon chains in each dimer are in the usual plane zigzag conformation but the other two are markedly deformed by rotations about single bonds. The small distance between copper atoms in a dimer is 2.565 A which is similar to that in copper acetate monohydrate.