Mn(HPO3): A new manganese (II) phosphite with a condensed structure

摘要

A new manganese (II) phosphite with the formula Mn(HPO3) has been synthesised under mild hydrothermal conditions and autogenous pressure. Large pink coloured single crystals were obtained, allowing the resolution of the structure by x-ray diffraction. Mn(HPO3) crystallises in the P2(t)/c monoclinic space group with a = 8.036(3) angstrom, b = 8.240(3) angstrom, c = 10.410(3)angstrom, beta = 124.73(3)degrees and Z = 8. The structure consists of a three-dimensional, compact framework of edge sharing MnO6 octahedra linked to phosphite groups via oxygens. The presence of the phosphite anion has been confirmed by IR spectroscopy. Mn(HPO3) presents a high thermal stability limit of 580 degrees C, before rapid transformation to Mn2P2O7 occurs. Photoluminescence and diffuse reflectance spectroscopy studies show the presence of high spin Mn(II) in significantly distorted octahedral coordination with Dq and Racah parameters of Dq = 820, B = 910 and C = 3135 cm(-1). The ESR spectra, performed at different temperatures, are isotropic with a g-value of 2.00(l). Magnetic measurements indicate global antifierrornagnetic interactions with a ferromagnetic transition at 15 K, attributed to a canting of the antiferrornagneticaly aligned spins. (c) 2005 Elsevier Inc. All rights reserved.