关键词: 二价稀土碘化物, 一步合成法, 晶体结构

Abstract: In this paper two types of compounds [ATmI₃(A=K, Rb, Cs) and A₄TmI₆(A=Rb, Cs)] were synthesized by one-step procedure and their crystal structures were determined by X-ray powder diffraction. The crystal structures of CsTmI₃, RbTmI₃ and KTmI₃ are orthorhombic ones. CsTmI₃: a =0.8689(3) nm, b =1.2339(4) nm, c =0.8565(3) nm, space group: Pnma, Z =4; RbTmI₃: a =1.0381(3) nm, b =0.4686(3) nm, c =1.7256(9) nm; space group: Pnma, Z=4; KTmI₃: a =0.4576(2) nm, b =1.5133(20) nm, c = 1.1679(6) nm, space group: Cmcm, Z =4; The linking manner among the structural unit [TmI₆] of octahedral in the three kinds of structures are different and they are corner-sharing, edge-sharing and both corner-and edge-sharing separately. The coordination number of atom of Cs, Rb and K decreases orderly and they are 10, 9 and 8. The structures of Cs₄TmI₆ and Rb₄TmI₆ belong to K₄CdCl₆-type(trigonal, space group: R3 c, Z =6). Rb₄TmI₆: a = 1.41714(9) nm, c =1.7473(1) nm, Cs₄TmI₆: a =1.4516(1) nm, c =1.8292(2) nm.

Key words: Divalent rare earth iodides, One-step synthesis procedure, Crystal structure