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本文用差热分析、X射线物相分析及点阵常数的精确测定等方法研究了新化合物Sr2CaMoO6的相变,证明该化合物在(767±5)℃存在一级位移型相变。低温相α-Sr2CaMoO。属正交晶系,空间群为Pmm2,室温时点阵常数为:α=8.1933?,b=5.7611?,c=5.8410?。测量密度Dm=4.97g/cm3,单位晶胞内具有2个化学式量。高温相β-Sr2CaMoOA new compound Sr2CaMoO6 has been synthesized by solid stare sintering. The phase transition of this compound was investigated by means of DTA, X-ray powder diffraction, precise measurement of lattice parameters and other methods. It is discovered that the compound has a displacive phase transition of the first order at (767±5)℃. The low temperaiure phase, or Sr2CaMoO6, belongs to orthorhombic system, with space group Pmm2, its lattice parameters at room temperature are:a = 8.1933?, b = 5.7611? and c=5.8410?, the measured density is Dm= 4.97g/cm3, and each unit cell contains two formula weight. The high temperature phase, β-Sr2CaMoO6, belongs to the cubic system, with space group Fm3m and the lattice parameter is α = 8.281? at 800℃; Z = 4. The calculated density is Dx= 4.76g/cm3.The crystal structures of α Sr2CaMoO6 and β-Sr2CaMoO6 was also determined by means of the X-ray polycrystal diffraction method. The character of the structure and the factors influencing phase transition temperature are discussed.
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物理学报. 1992, 41(6): 937-947.
doi: 10.7498/aps.41.937.
新化合物——Sr2CaMoO6的相变与晶体结构
- 收稿日期: 1990-12-30
- 刊出日期: 1992-03-05
摘要: 本文用差热分析、X射线物相分析及点阵常数的精确测定等方法研究了新化合物Sr2CaMoO6的相变,证明该化合物在(767±5)℃存在一级位移型相变。低温相α-Sr2CaMoO。属正交晶系,空间群为Pmm2,室温时点阵常数为:α=8.1933?,b=5.7611?,c=5.8410?。测量密度Dm=4.97g/cm3,单位晶胞内具有2个化学式量。高温相β-Sr2CaMoO
English Abstract
PHASE TRANSITION AND CRYSTAL STRUCTURE OF A NEW COMPOUND ——Sr2CaMoO6
- Received Date:
30 December 1990
- Published Online:
05 March 1992
Abstract: A new compound Sr2CaMoO6 has been synthesized by solid stare sintering. The phase transition of this compound was investigated by means of DTA, X-ray powder diffraction, precise measurement of lattice parameters and other methods. It is discovered that the compound has a displacive phase transition of the first order at (767±5)℃. The low temperaiure phase, or Sr2CaMoO6, belongs to orthorhombic system, with space group Pmm2, its lattice parameters at room temperature are:a = 8.1933?, b = 5.7611? and c=5.8410?, the measured density is Dm= 4.97g/cm3, and each unit cell contains two formula weight. The high temperature phase, β-Sr2CaMoO6, belongs to the cubic system, with space group Fm3m and the lattice parameter is α = 8.281? at 800℃; Z = 4. The calculated density is Dx= 4.76g/cm3.The crystal structures of α Sr2CaMoO6 and β-Sr2CaMoO6 was also determined by means of the X-ray polycrystal diffraction method. The character of the structure and the factors influencing phase transition temperature are discussed.
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