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

U-Chan Chung Seu (1) , José L. Mesa (2) , José L. Pizarro (1) , Veronique Jubera (3) , Luis Lezama (2) , María I. Arriortua (1) , Teófilo Rojo (2)

1 Departamento de Mineralogía-Petrología, Facultad de Ciencia y Tecnologia
2 Departamento de Química Inorgánica, Facultad de Ciencia y Tecnologia
3 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

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 P21/c monoclinic space group with a=8.036(3) Å, b=8.240(3) Å, c=10.410(3) Å, β=124.73(3)° 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 °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(1). Magnetic measurements indicate global antiferromagnetic interactions with a ferromagnetic transition at 15 K, attributed to a canting of the antiferromagneticaly aligned spins.

Mots clés: Hydrothermal synthesis; X-ray diffraction; UV/v is and luminescent spectroscopies; Magnetic behavior

Domaines: Matériaux

U-Chan Chung Seu, José L. Mesa, José L. Pizarro, Veronique Jubera, Luis Lezama, et al.. Mn(HPO3): a new manganese (II) phosphite with a condensed structure. Journal of Solid State Chemistry, 2005, 178 (9), pp.2913-2921. ⟨10.1016/j.jssc.2005.06.038⟩. ⟨hal-00096640⟩