Lanthanoid(III) oxide chloride oxoselenates(IV): A fascinating class of multinary compounds

Cs7Nd11(SeO3)12Cl16: First Noncentrosymmetric Structure among Alkaline-Metal Lanthanide Selenite Halides

“…In the present study, we report the synthesis and crystal structure of a new selenite chloride of neodymium and cesium with the composition Cs 7 Nd 11 (SeO 3 ) 12 Cl 16 . This compound extends the M x Ln 11 (SeO 3 ) 12 Hal x+9 (M = alkaline metal; Ln = La, Pr, Nd, Sm; Hal = Cl, Br) family 7,9,13−15 and demonstrates a NC structure. As far as we know, this is the first example of a NC structure among the M x Ln 11 (SeO 3 ) 12 Cl y compounds.…”

“…Recently, successful preparations of the mixed-anion selenite halides of lanthanides and alkaline metals have been reported. − One can expect that these compounds could form a relatively large family because of their ability to combine different structural blocks, such as (Ln 11 (SeO 3 ) 12 , CsCl-like blocks, and layers of halide atoms, as demonstrated by the selected examples of the CsSm 21 (SeO 3 ) 24 Br 16 , Rb 6 LiLn 11 (SeO 3 ) 12 Cl 16 (Ln = Pr, Nd), , and Cs 3 La 11 (SeO 3 ) 12 Cl 12 structures . All rare-earth selenite halides known so far are centrosymmetric.…”

Sm3O2Sm[SeO3]4 and Sm3O2Cl[SeO3]2: A Monoclinic Form of Samarium Oxide Oxoselenate(IV) and a Samarium Oxide Chloride Oxoselenate(IV) both with 1∞{[O2Sm3]5+} Chains

“…In all these compounds with extra oxygen atoms, oxide‐centered ( RE 3+ ) 4 tetrahedra are found, a crystal chemistry that has been extensively reviewed by Krivovichev et al, These [O RE 4 ] 10+ tetrahedra ( RE = Sm – Tm) form one‐dimensional infinite chains 1 ∞ {[O RE e 4/2 ] 4+ } (e = edge‐connecting) via trans ‐edge sharing in the tetragonal RE 2 O[SeO 3 ] 2 representatives. In the first chloride‐containing phases with extra oxygen atoms and the composition RE 3 O 2 Cl[SeO 3 ] 2 ( RE = Tb, Dy, Er), these [O RE 4 ] 10+ tetrahedra join together to analogous 1 ∞ {[O RE e 4/2 ] 4+ } strands, but two of these are further condensed to 1 ∞ {[O 2 RE 3 ] 5+ } double chains. For the composition RE 4 O 3 Cl 2 [SeO 3 ] 2 ( RE = Er, Yb), six [O RE 4 ] 10+ tetrahedra get edge‐fused to [O 6 RE 12 ] 24+ units first, which are the basic module of the crystal structure.…”