Phase Transitions in the Na3M2(PO4)2F3 Family (M=Al3+, V3+, Cr3+, Fe3+, Ga3+): Synthesis, Thermal, Structural, and Magnetic Studies
作者:J.-M. Le Meins、M.-P. Crosnier-Lopez、A. Hemon-Ribaud、G. Courbion
DOI:10.1006/jssc.1999.8447
日期:1999.12
crystallographic transitions which involve three modifications: α, β, and α. The room temperature (β) phases can be split into two groups: the first (β1), with M=Al3+, Cr3+, Ga3+, crystallizes in the space group P42/mbc (a=12.406(2) Å, c=10.411(2) Å, Z=8 for M=Al3+) whereas the second group (β3) with M=V3+, Fe3+ crystallizes in the space group P42/mnm (a=9.047(2) Å, c=10.705(2) Å, Z=4 for M=V3+). On the
通过水热合成或固相合成法制备了所研究的化合物Na 3 M 2(PO 4)2 F 3(M = Al 3+,V 3+,Cr 3+,Fe 3+,Ga 3+),并对其进行了表征。通过热分析(TGA,DTA,DSC),粉末和单晶X射线工作或中子衍射。还使用了其他几种表征方法,例如TEM衍射,IR,磁性和Mössbauer光谱。这些化合物具有两个晶体学转变,涉及三个修饰:α,β和α。室温(β)相可以被分成两组:第一(β 1),以中号=铝3+,铬3+,镓3+,结晶在空间群P 4 2 / MBC(一个= 12.406 (2)埃,c ^ = 10.411(2)埃,ž为= 8中号=铝3+),而第二组(β 3)与中号= V 3+,铁3+结晶在空间群P 4 2 /mnm(a = 9.047(2)Å,c = 10.705(2)Å,M = V 3+时Z = 4 )。另一方面,所有高温(α)相都采用相同的空间群I 4