Mild hydrothermal synthesis of Cu(SeO(3)).2H(2)O: structural characterization, thermal, spectroscopic and magnetic
Aitor Larrañaga1, José L Mesa, Luis Lezama
1Departamento de Mineralogía y Petrología, Universidad del País Vasco/EHU, Apdo. 644, E-48080 Bilbao. Spain.
Abstract:
Cu(SeO(3)).2H(2)O has been synthesized by hydrothermal technique under autogeneous pressure. The compound crystallizes in the P2(1)2(1)2(1) orthorhombic space group. The unit cell parameters are a=6.672(1), b=9.167(1) and c=7.372(1) A with Z=4. The crystal structure has been refined using the Rietveld method. The limit of thermal stability is 130 degrees C, temperature at which the water content is lost. Above 470 degrees C the compound decomposes in SeO(2)(g) and CuO(s). The IR spectrum shows the characteristic bands of the (SeO(3))(2-) oxoanion and water molecules. An intense absorption band characteristic of Cu(II) cations in five-coordination is observed in the diffuse reflectance spectrum. The ESR spectra are isotropic from room temperature to 4.2K, with g=2.13(1). Magnetic measurements confirm the existence of a global antiferromagnetic behavior with a spin canting phenomenon detected at, approximately, 30K.
