space group, C92ν-Pna21. The similarities between the vibrational spectra of α-Ba2P2O7 and α-Sr2P2O7 suggested that α-Ba2P2O7 is isostructural with α-Sr2P2O7. Differences were noted in the vibrational spectra of monoclinic α-Ca2P2O7 and the two orthorhombic α-phases, α-Sr2P2O7 and α-Ba2P2O7, which were related to differences in their crystal structures. The P2O74−-anions of all three compounds contained
拉曼光谱和中间红外吸收光谱(4000-200厘米-1)分别为α-
钙测量2 P 2 ö 7,α-
锶2 P 2 ö 7,和α-的Ba 2 P 2 ö 7。使用因子组分析解释了这些光谱,并进行了谱带分配。在α-SR的红外和拉曼光谱Noncoincidences 2 P 2 ö 7表明,该材料具有中心对称空间群d 16 2 Ĥ -晶
PNma而非非中心对称空间群,c ^ 9 2 ν -
PNA 2 1。α-Ba中的振动光谱之间的相似2 P 2 ö 7和α-
锶2 P 2 ö 7表明,α-的Ba 2 P 2 ö 7是同构用α-
锶2 P 2 ö 7。差异单斜的振动光谱是注意到α-的Ca 2 P 2 ö 7和两个正交α-相,α-
锶2 P 2 ö 7和α-巴2 P 2 O 7,这与它们的晶体结构差异有关。所有这三种化合物的P 2 O 7 4-阴离子均具有非线性的POP键角。