摘要
The dynamic process of the ionic valence changing from Eu^(2+) to Eu^(3+) in EuF_2 at high temperature has been investigated by ESCA, high,temperature X-ray diffraction, high temperature spectrum, high temperature magnetic Isusceptibility and Mssbauer spectrum. It has been shown that the formed Eu^(3+) exists in different compounds when EuF_2 is heated to high temperature in different atmospheres. In air, Eu^(3+) exists in the form of hexagonal EuOF, in nitrogen, in the form of orthogonal EuF_3 and non-hexagon EuOF. This is because decomposition or disproportionation of EuF_2 is different with different atmospheres. The magnetic susceptibility measurement showed quantitatively that the change rate from Eu^(2+) to Eu^(3+) is about 95% in air, and about 75% in nitrogen when it is heated to 900℃. A small amount of Eu^(2+) coexists with Eu^(3+) in the final product.
The dynamic process of the ionic valence changing from Eu<sup>2+</sup> to Eu<sup>3+</sup> in EuF<sub>2</sub> at high temperature has been investigated by ESCA, high,temperature X-ray diffraction, high temperature spectrum, high temperature magnetic Isusceptibility and Mssbauer spectrum. It has been shown that the formed Eu<sup>3+</sup> exists in different compounds when EuF<sub>2</sub> is heated to high temperature in different atmospheres. In air, Eu<sup>3+</sup> exists in the form of hexagonal EuOF, in nitrogen, in the form of orthogonal EuF<sub>3</sub> and non-hexagon EuOF. This is because decomposition or disproportionation of EuF<sub>2</sub> is different with different atmospheres. The magnetic susceptibility measurement showed quantitatively that the change rate from Eu<sup>2+</sup> to Eu<sup>3+</sup> is about 95% in air, and about 75% in nitrogen when it is heated to 900℃. A small amount of Eu<sup>2+</sup> coexists with Eu<sup>3+</sup> in the final product.
基金
Project supported by the National Natural Science Foundation of China.
