face-sharing octahedra, linked by bent diphosphates P2O7 (P–O–P∼156°). Fe4(P2O7)3 is antiferromagnetic below TN=50 K. The magnetic structure has been determinated by means of powder neutron diffraction. There are four antiferromagnetic iron sublattices corresponding to the four crystallographically distinct iron atoms. The magnetic moments are antiferromagnetically coupled inside the Fe2O9 dimers, in agreement
在940℃,
氧气下由Fe(PO 3)3和FePO 4制备Fe 4(P 2 O 7)3。晶胞是单斜晶系,空间群P 2 1 / n,a = 7.389(2)Å,b = 21.337(1)Å,c = 9.517(2)Å,β = 90(1)°,Z = 4,晶体结构已经通过直接方法和傅立叶差分合成法从单晶中确定,并精炼为R = 0.10(R w= 0.09)。三维框架是由两个面共享八面体的Fe 2 O 9簇建立的,它们由弯曲的二
磷酸盐P 2 O 7(P–O–P〜156°)连接。Fe 4(P 2 O 7)3在T N = 50 K以下为反
铁磁性。磁性结构已通过粉末中子衍射法确定。有四个反
铁磁性的
铁亚晶格,对应于四个在晶体学上不同的
铁原子。符合古德诺规则,在Fe 2 O 9二聚体内部将磁矩反
铁磁耦合。它们与Ç轴并具有4.55(5)μ乙在1.7 K的磁相互作用进行了讨论值。Mössbauer光谱分别在顺磁性