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 P1̄, and
formulated as [Ln6(H2O)25(MV12O38)(HMV13O38)]·nH2O ((1) Ln = La, M = Mn, and n ≈ 31; (2) Ln = Ce, M = Mn,
and n ≈ 29; (3) Ln = Pr, M = Mn, and n ≈ 31; (4) Ln = La, M = Ni, and n ≈ 28; (5) Ln = Pr, M = Ni, and
n ≈ 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 Oh symmetry, which consists of 13 entire edge-sharing MO6 (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.