title: Poly[[hexa-aqua-bis-(μ3-pyrimidine-4,6-dicarboxyl-ato)dicalcium] dihydrate].
abstract: The polymeric structure of the title compound, {[Ca2(C6H2N2O4)2(H2O)6]·2H2O} n , is built up of mol-ecular layers composed of Ca(II) ions bridged by both ligand N and O atoms with one of the O atoms being bis-monodentate. Two adjacent Ca(II) ions are bridged by these O atoms, forming a centrosymmetric dimer which is the building unit of the structure. The dimers are nodes of a cross-linked mol-ecular layer parallel to (101). The Ca(II) ion is coordinated by two bidentate ligands, one monodentate ligand and three water mol-ecules in the form of a distorted polyhedron with a coordination number of eight. Solvate water mol-ecules located between adjacent layers participate as donors and acceptors in a system of hydrogen bonds in which coordinating water mol-ecules also act as donors and non-coordinating carboxyl-ate O atoms act as acceptors.
authors.affiliation: Institute of Nuclear Chemistry and Technology, ul.Dorodna 16, 03-195 Warszawa, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Starosta
authors.forename: Janusz
authors.initials: J
authors.lastname: Leciejewicz