Syntheses, crystal structures and magnetic properties of three new silver manganese(ii) or manganese(iii) mixed metal iodates

Abstract

Systematic explorations of new compounds in the unexplored Ag+–Mn2+/Mn3+–iodate system led to three new silver Mn2+ (or Mn3+)-mixed metal iodates, namely, AgMn(IO3)3, AgMn(IO3)4 and Ag3Mn(IO3)6. These compounds feature the same building units of MnO6 octahedron and IO3, but the different coordination modes of the iodate groups in these compounds led to three different types of anionic structures ranging from a zero-dimensional (0D) cluster to a two-dimensional (2D) layer. Interestingly, the dimensions of the anionic structure decrease with an increase in the IO3/Mn molar ratio in the formula. AgMn(IO3)3 exhibits a 2D [Mn2(IO3)6]n2n− anionic layer in which the Mn2O2 rings are further decorated by terminal iodates and interconnected by bidentate and tridentate bridging iodate groups. AgMn(IO3)4 displays a one-dimensional (1D) [Mn(IO3)4]nn− anionic chain in which each pair of MnO6 octahedra is bridged by a pair of IO3 groups, and within the chain each manganese center is also attached with two terminal iodate groups from both sides of the chain. Ag3Mn(IO3)6 features isolated 0D [Mn(IO3)6]3− anions. The Ag+ cations in all three compounds act as spacers between these anions. Optical, thermal stability and magnetic susceptibility measurements for AgMn(IO3)3 and AgMn(IO3)4 have also been performed.