Poly[[aquacopper(I)-mu-bromo]-mu-(5-methylpyrazine-2-carboxylato)-kappa N-3(4): O,N-1-[diaquacopper(II)]-mu-(5-methylpyrazine-2-carboxylato)-kappa 3O,N-1 : N-4-[aquacopper(I)-mu-bromo]]

In the structure of the title compound, [Cu3Br2(C6H5N2O2)(2)(H2O)(4)], both copper(I) and copper(II) cations are present. The copper(II) cations are l ocated on centres of inversion and are coordinated by two N atoms and two c arboxylate O atoms from two symmetry-related 5-methylpyrazine-2-carboxylate anions, with two water molecules completing a distorted octahedron. The co pper(I) cations are coordinated by the second N atom of the 5-methylpyrazin e-2-carboxylate anion, one water molecule and two bromide anions within a d istorted tetrahedron. Each of the bromide anions connects two symmetry-equi valent copper(I) cations to form zigzag-like CuBr chains. These chains are connected by the [diaquabis(5-methylpyrazine-2-carboxylato)]copper(II) comp lexes, forming corrugated sheets parallel to (100). The CuBr chains and the sheets are connected via O-H . . .O and O-H . . . Br hydrogen bonding.