catena-Poly[[[bis­(3-amino­pyrazine-2-carboxyl­ato)triaqua­praseodymium(III)]-μ-3-amino­pyrazine-2-carboxyl­ato-[(3-amino­pyrazine-2-carboxyl­ato)diaqua­formatopraseodymium(III)]-μ-3-amino­pyrazine-2-carboxyl­ato] hexa­hydrate]

The asymmetric unit of the polymeric title compound, {[Pr(2)(C(5)H(4)N(3)O(2))(5)(CHO(2))(H(2)O)(5)]·6H(2)O}(n), has two independent Pr(III) atoms; one is coordinated by two water mol-ecules and the other by three water mol-ecules. The first is N,O-chelated by three 3-amino-pyrazine-2-carboxyl-ate ions, whereas the second is chelated by two carboxyl-ate ions; both exist in a monocapped square-anti-prismatic geometry. The polymeric chains that run along the a axis inter-act with the lattice water mol-ecules, generating a three-dimensional hydrogen-bonded network. The formate ion is disordered over two positions with respect to the non-coordinated atoms in a 1:1 ratio.