M4F20 tetramers with the transition elements occupying the corners of the rhombus. In the case of RuF5 the magnetic susceptibility vs. temperature curve shows a broad maximum at T ⋍ 40 K. Neutron diffraction experiments below and above this temperature show that this maximum does not correspond to a magnetic three-dimensional ordering. Theoretical calculations based on isolated tetra-nuclear clusters of
摘要 五
氟化物 MF5 (M = Ru, Rh, Os, Ir, Pt) 的结构单元由
M4F20 四聚体组成,过渡元素占据菱形的角。在 RuF5 的情况下,磁化率与温度曲线在 T ⋍ 40 K 处显示出一个广泛的最大值。低于和高于该温度的中子衍射实验表明该最大值不对应于磁三维排序。已应用基于相同 S = 3 2 自旋的孤立四核簇的理论计算。簇内交换相互作用是反
铁磁性的。磁化率数据的拟合导致交换常数 J k = -8.3 K。