金属クラスター化合物Nb₆I_11-xBr_xおよびY_2-xM_xC₂Br_2-yI_y (M=Sr, La, Lu, Th) の結晶構造と物性

抄録

Crystal structure, chemical bonding and physical property are discussed for the metal-rich cluster compound Nb₆I_11-xBr_x containing discrete clusters and the layered cluster compound Y_2-xM_xC₂Br_2-yI_y, focusing on the effect of replacement by other atoms having different mass, size and bonding. Nb₆I_11-xBr_x undergoes a spin cross-over phase transition and with increasing Br content the transition temperature shifts from 274 to 170 K. The highest superconducting transition temperature in the yttrium ethenide halides occurs at a intermediate composition rather than at each end-member.