物理化学学报 >> 2002, Vol. 18 >> Issue (07): 624-628.doi: 10.3866/PKU.WHXB20020711

研究论文 上一篇    下一篇

新型十八核聚氧钼酸盐的合成与结构

刘广;章士伟   

  1. 北京大学化学与分子工程学院 分子动态与稳态结构国家重点实验室,北京　100871
  • 收稿日期:2001-12-14 修回日期:2002-03-12 发布日期:2002-07-15
  • 通讯作者: 章士伟 E-mail:zsw@chem.pku.edu.cn

Synthesis and Structure of a Novel 18Mo Polyoxomolybdate

Liu Guang;Zhang ShiWei   

  1. State Key Laboratory for Structural Chemistry of Unstable and Stable Species,College of Chemistry and Molecular Engineering, Peking University, Beijing　100871
  • Received:2001-12-14 Revised:2002-03-12 Published:2002-07-15
  • Contact: Zhang ShiWei E-mail:zsw@chem.pku.edu.cn

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摘要： 合成了新化合物(NH4)6•[Ca2(H2O)6(CH3COO)2]•{Ca@[O52(OH)4(CH3COO)2]}•14H2O，并运用元素分析和单晶X衍射对其结构进行了表征.测定结果证实,该化合物由十八个钼氧八面体相互连接而成，呈现一种有趣的环状结构.在环的中心有一个Ca2＋离子，它通过与环上的四个酰氧配位而与环骨架相连.有十个钼原子呈正六价，而其余八个钼原子呈正五价，且有Mo－Mo键存在.环上还有配位相连的四个乙酸配体.在环的上下各有两个Ca2＋离子，它通过与该环和其它环上的氧原子配位而把环连成一维链状结构.晶体属三斜晶系，空间群P1，晶胞参数：a=1.055 2(2) nm， b=1.515 0(3) nm， c=1.544 9(3) nm， α=60.84(3)， β=88.00(3)， γ=71.21(3)°，V=2.019 4(7) nm3， R1=0.036 6（对可观察点）， wR2=0.083 3（对独立点）.

关键词: 钼, 聚氧钼酸盐, 环状结构, 链状结构, 晶体结构

Abstract: A new compound (NH4)6•[Ca2(H2O)6(CH3COO)2]•{Ca@[O52(OH)4(CH3COO)2]}•14H2O was prepared and the structure was determined by Xray diffraction analysis. The compound shows an interesting girdlelike structure that is composed of eighteen Mo－O octahedra. There is a Ca2＋ cation in the center of the girdle, which connects to the girdle backbone by bonding to four oxygen atoms of the girdle. The valences of ten Mo atoms are ＋6 while those of the other eight Mo atoms are ＋5, between which Mo－Mo bonds are found. Four acetic ligands connect to the girdle. The girdles link into 1D chains by the Ca2＋ cations above and below the girdle bonding to the backbone oxygen atoms. This compound is triclinic, space group P1, a=1.055 2(2)nm, b=1.515 0(3)nm, c=1.544 9(3)nm, α=60.84(3), β=88.00(3), γ=71.21(3)°, V=2.019 4(7)nm3, R1=0.036 6 and wR2=0.083 3.

Key words: Molybdenum, Polyoxomolybdate, Girdlelike structure, Chainlike structure, Crystal structure