关键词: 钒酸盐, 镧化合物, Ｘ射线衍射分析, 结构分析, 钙化合物, 相变, 稀土化合物, 锶化合物

LaSr2-xCaxV3O9眣 (x = 0.0, 0.67, 1.0, 1.33, 2.0; y = -0.18, 0.08, -0.04, 0.02, -0.26, resp.) have been synthesized thermally. X-ray powder diffraction results indicate that they are single compounds Their lattice constants are reported. The structure of LaSr2-xCaxV3O9眣 changed from cubic to orthorhombic and back to cubic with the increase of Ca content. The results of wt. gain in TG and of XPS curves show that V with lower valent state is oxidized to higher valent state at higher temperature The O content of new compounds are calculated from the wt. gain. V3+ and V4+ may coexist in LaSr2-xCaxV3O9眣. These compounds have low elec. resistivity.

Key words: VANADATE, LANTHANUM COMPOUNDS, X-RAY DIFFRACTION ANALYSIS, STRUCTURAL ANALYSIS, CALCIUM COMPOUDS, PHASE TRANSFORMATION, RARE EARTH COMPOUNDS, STRONTIUM COMPOUNDS