Structure, vibrational and magnetic characteristics of LiYbX2O8 (X = W, Mo) single-crystals

Mixed occupancy: the crystal structure of scheelite-type LiLu[MoO4]2

“…Since Na + and K + cations are larger than Li + cations and thus closer to the size of Ln 3+ cations, it is not astonishing that the crystal volumes of NaLn[MoO 4 ] 2 and KLn[MoO 4 ] 2 compounds are considerably larger than those of the respective LiLn[MoO 4 ] 2 series. In case of the larger lanthanoids, lithium-containing scheelite-type structures according to the formula LiLn[MoO 4 ] 2 with Ln = Ce 3+ (Egorova et al, 1982) and Nd 3+ (Kolitsch, 2001) are known so far, while for Yb 3+ as a representative of the smaller lanthanides, the crystal structure shows deviations from the Laue group 4/m, crystallizing in space group I4 (Volkov et al, 2005;Armand et al, 2021). In all the aforementioned compounds, the rather small Li + cations assume a mixed occupancy with the respective lanthanoid, which is also found in the crystal structures of e.g.…”