Two-Dimensional Lanthanide Heteropolyvanadates of Manganese(IV) and Nickel(IV) Containing Two Types of Heteropoly Anions with 1:13 and 1:12 Stoichiometry

Reactions of 1:13 heteropoly anions [MV13O38](7-) (M = Mn, Ni) and lanthanide cations Ln3+ (Ln = La, Ce, or Pr) produce five isomorphic compounds, which are crystallized in the triclinic crystal system, space group P1, and formulated as [Ln6(H2O)25(MV12O38)(HMV13O38)].nH2O ((1) Ln = La, M = Mn, and n approximately 31; (2) Ln = Ce, M = Mn, and n approximately 29; (3) Ln = Pr, M = Mn, and n approximately 31; (4) Ln = La, M = Ni, and n approximately 28; (5) Ln = Pr, M = Ni, and n approximately 33). These compounds are two-dimensional polymeric structures constructed by hydrated lanthanide cations and two types of heteropoly anions, [MV13O38](7-) and [MV12O38](12-). In contrast to the previous reported 1:13 heteropoly anions, all with disordered structures, [MV13O38](7-) clusters in 1-5 are non-disordered with a distinct mode. The second kind of anionic cluster [MV12O38](12-) with O(h) symmetry, which consists of 13 entire edge-sharing MO(6) (M = V, Mn or Ni) octahedra, has not been reported hitherto. The emergence of the new cluster may be correlated to the six capping lanthanide cations surrounding it with a stabilization effect. In this paper, the syntheses and structures of the five polymeric lanthanide heteropolyvanadates of manganese(IV) and nickel(IV) have been presented.