title: Piperazine-1,4-diium bis-(2-carb-oxy-1H-pyrazole-4-carboxyl-ate) tetra-hydrate.
abstract: The asymmetric unit of the title compound, C(4)H(12)N(2) (2+)·2C(5)H(3)N(2)O(4) (-)·4H(2)O, comprises one-half of a piperazine-1,4-diium cation, which lies on an inversion centre, a 2-carb-oxy-1H-pyrazole-4-carboxyl-ate anion and two water mol-ecules. An extensive network of inter-molecular O-H⋯O, N-H⋯O, N-H⋯N and C-H⋯O hydrogen bonds between the cations, anions and water mol-ecules leads to a three-dimensional supra-molecular framework.
authors.affiliation: Key Laboratory for Organic Electronics & Information Displays (KLOEID) and Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications (NUPT), Nanjing 210046, People's Republic of China.
authors.forename: Xin-Hui
authors.initials: XH
authors.lastname: Zhou