Crystal structure and magnetic properties of manganese (II) mellitate, [Mn 2{C 6(COO) 6}(H 2O) 6][Mn(H 2O) 6]·2H 2O with two-dimensional layered structure and three-dimensional hydrogen bonding networks

Abstract

The crystal and molecular structure of manganese (II) mellitate, [Mn 2{C 6(COO) 6}(H 2O) 6][Mn(H 2O) 6]·2H 2O, has been determined by X-ray structure analysis. The complex crystallizes in the monoclinic system, space group C2/ c, with cell constants a = 23.298(3), b = 6.456(3), c = 17.072(2) A ̊ , β = 101.01(1)° and Z = 4 . The structure was solved and refined to R = 0.029 ( R w = 0.036). There are two types of manganese ions in the structure. Mn(1) is situated on a crystallographic center of symmetry and bound to six water molecules while Mn(2) is coordinated octahedrally by three water molecules and three carboxylate oxygen atoms. The major structure feature is that the polyanion formed by Mn(2) ions and the mellitate hexanions with composition of [Mn 2{C 6(COO) 6}(H 2O) 6] n 2 n− possesses a two-dimensional layered structure which is linked through a complex three-dimensional hydrogen bonding associated with the Mn(1) cation [Mn(H 2O) 6] 2+ and the water of crystallization. Analysis of variable-temperature magnetic susceptibility data (5.0–300 K) shows that the complex displays antiferromagnetic exchange.