[Cr(bipy) (C2O4)2]^- - A versatile building block for the design of heteropolymetallic systems 2. Syntheses and crystal structures of CuCr2(bipy)2(μ-C2O4) 2(C2O4)2(H2O) 2·1¹/2H2O and (AgCr(bipy) Journal Articles