ETHYLENEDIAMMONIUM BIS(MONOHYDROGEN OXALATE) MONOHYDRATE AND 2 MODIFICATIONS OF TRIMETHYLENEDIAMMONIUM BIS(MONOHYDROGEN OXALATE) MONOHYDRATE

Essential features of the crystal structures of [NH3(CH2)(n)NH3 ](2+). 2(HOOCCOO)(-).H2O (0 < n < 6) are preserved through changes of conform ation and space group. In each of the title structures, ethylenediammo nium bis(monohydrogen oxalate) monohydrate, C2H10N22+.2C(2)HO(4)(-).H2 O, and two modifications of trimethylenediammonium bis(monohydrogen ox alate) monohydrate, C3H12N22+.2C(2)HO(4)(-).H2O, the cation and the wa ter molecule occupy special positions. Linear hydrogen-bonded (Hoxalat e)(n) chains are parallel to and connected to hydrogen-bonded spirals in which the water molecules link anions and cations. Unique to each s tructure are additional hydrogen bonds, perpendicular to these chains, which connect cations and anions into three-dimensional arrays.