In the structure of the hydrated title salt, (C4H7N2)2[Sn(C2O4)2(OH)2]·H2O, the asymmetric unit comprises one stannate(IV) dianion, two organic cations and one water mol-ecule of crystallization. The [Sn(C2O4)2(OH)2](2-) dianion consists of an Sn(IV) atom chelated by two oxalate anions and coordinated by two OH(-) ligands in a cis octa-hedral arrangement. Neighbouring anions are connected through O-H⋯O hydrogen bonds between hydroxide groups and non-coordinating oxalate O atoms into layers expanding parallel to (100). In addition, cations and anions are linked through N-H⋯O hydrogen bonds, and the water mol-ecule bridges two anions with two O-H⋯O hydrogen bonds and is also the acceptor of an N-H⋯O hydrogen bond with one of the cations. Weak C-H⋯O hydrogen bonds are also observed. The intricate hydrogen bonding leads to the formation of a three-dimensional network.
Keywords: crystal structure; hydrogen bonds; organotin(IV) complex.