Caesium Pentafluoroterbate, CsTbF₅

Alkali Metal (Li+–Cs+) Salts with Hexafluorochromate(V), Hexafluorochromate(IV), Pentafluorochromate(IV), and Undecafluorodichromate(IV) Anions

“…Determination of their crystal structures shows that the previously reported lattice constants were not correct. It should also be mentioned that, with the exception of the recently published crystal structures of AZrF 5 , [18,19] AHfF 5 , [20] and ATbF 5 , [21,22] no conclusive information was published on the structural arrangements of the A I M IV F 5 (M = transition metal) phases since 1967. [23] [CrF 6 ] 2-(Li-Cs) salts of alkali metals have been known for a long time.…”

“…308(sh.) 319 (7) δ CrF4 300 (30) 298 (27) 288 (20) δ CrF4 253 (25) 258 (31) 261 (46) δ CrF4 229 (22) 226 (18) (2) 174 (5) 166 (9) τ chain , lattice vib. …”

Synthesis and crystal structures of new mixed-valence terbium (III/IV) fluorides with a random distribution between Tb3+ and Tb4+

“…This unexpected surrounding of the Tb 4+ ion should be related to the statistical distribution of the Tb 3+ and Tb 4+ ions over a unique crystallographic site, whereas numerous crystallographic studies upon tetravalent terbium fluorides systematically revealed an 8-coordination for Tb 4+ ions. In the MF-TbF 4 (M = K, Rb, and Cs) binary systems, the mixed-valence exclusively appears for compositions corresponding to a tetrafluoride content greater than MF/MF 4 = 1, the MTbF 5 fluorides [8,9] corresponding to the upper limit of pure tetravalent terbium compounds. When free TbF 4 appears in the diphasic region, it partially decomposes and the resulting mixed-valence (III/IV) terbium fluorides that may be formed belong to the ternary MF-TbF 3 -TbF 4 system.…”

Stabilization of Th3+ ions into mixed-valence thorium fluoride

“…KTbF 5 , was highlighted in the KF-TbF 4 binary system (including K 3 TbF 7 , K 2 TbF 6 , K 7 Tb 6 F 31 and KTbF 5 ). Indeed, by the constraint for +4 terbium ions to be obligatorily in eight coordination in fluorinated environment [6][7][8][9][10][11], the combinations with potassium fluoride are limited. This obligation does not exist for Tb 3 + and a series of trivalent terbium fluorides covers all the composition range K 3 TbF 6 -KTb 3 F 10 (the intermediate fluorides are K 2 TbF 5 , KTbF 4 , and KTb 2 F 7 ).…”

“…In the present paper, we focus on thorium fluoride in order to investigate the stabilization of Th 3 + in a Th 3 + /Th 4 + mixed-valence compound. Among the numerous studies devoted to lanthanide and actinide fluorides, data on mixed-valence compounds were less reported in the literature [4][5][6][7][8][9][10][11][12][13][14][15][16][17].…”