Cu succinate was obtained by treating of naturally occuring azurite with detergent which presumedly contained succinic acid. The tetragonal structure of Cu(C4H4O4)H2O was established from X-ray single crystal diffraction, lambda (CuKalpha = 1.5418 Angstrom); space group P4(2)2(1)2; a = 8.853(4) Angstrom, c = 14.866(8) Angstrom, V = 1165.1 Angstrom(3); M = 197.63; D-x = 2.25 g/cm(3); Z = 8; mu = 5.049 mm(-1); F(000) = 792; R = 0.078 for 366 reflections. The new phase is characterized by a layered structure, which consists of Cu cations linked by chelating - bridging dicarboxylate anions. The structure is closely related to that of copper maleate hydrate.