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化学学报
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化学学报 ›› 1987, Vol. 45 ›› Issue (5): 426-431. 上一篇    下一篇

研究论文

水合稀土二氯醋酸盐的合成及热分解研究

熊为淼;吴淑荣;孟艳   

  1. 西北大学化学系;西北大学热化学研究室
  • 发布日期:1987-05-15

Synthesis and thermal decomposition studies on rare earth dichloroacetate hydrates

XIONG WEIMIAO;WU SHURONG;MENG YAN   

  • Published:1987-05-15

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541

被引次数

4

合成了La,Ce,Nd,Sm,Eu,Gd二氯醋酸盐,经化学分析,热重法和五氧化二磷真空千燥脱水法确定组成为Ln(CHCl2COO)3.nH2O(n=2,Ln=La,Ce,Nd;n=1.5,Ln=Sm;n=1.25,Ln=Eu;n=1,Ln=Gd),它们均属新水合物.用DTA-TG-DTG并用技术并辅以化学分析和红外光谱技术研究了其热分解机理,实验证明,由室温至600℃范围内,它们均发生三步主要反应:水合盐脱水变为无水盐;无水盐分解为中间产物,Ln2(OH)Cl5.3H2O[Eu盐分解为Eu2(OH)Cl5.2H2O];中间产物进一步分解为LnOCl[Ce盐为CeO2].并观察到无水盐和氯氧化物形成温度皆与原子序数呈现镧系"双一双效应".

关键词: 反应机理, 红外分光光度法, 镧化合物, 钕化合物, 水合物, 铕化合物, 铈化合物, 热重量分析, 差热分析, 稀土化合物

Ln(CHCl2CO2)3.nH2O (I; n = 2, Ln = La, Ce, Nd; n = 1.5, Ln = Sm; n = 1.25, Ln = Eu; n = 1, Ln = Gd) were prepared and characterized by chem. anal., thermogravimetry and dehydration over P2O5. The mechanism of thermal decomposition was studied by DTA, TG, and DTG techniques, chem. anal. and IR spectra. The thermal decomposition of I takes place at 25-600?through 3 major steps, viz. the hydrated salts dehydrate and are then decomposed to intermediates, Ln2(OH)Cl5.3H2O [Eu salt salt to Eu(OH)Cl5.2H2O], which are further decomposed to LnOCl (Ce salt to CeO2). The double-double effects in the lanthanide series were observed

Key words: REACTION MECHANISM, INFRARED SPECTROPHOTOMETRY, LANTHANUM COMPOUNDS, NEODYMIUM COMPOUNDS, HYDRATE, EUROPIUM COMPOUNDS, CERIUM COMPOUNDS, THERMOGRAVIMETRY, DIFFERENTIAL THERMAL ANALYSIS, RARE EARTH COMPOUNDS

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