Tb2Se2O7: Terbium(III) Oxide Oxoselenate(IV) according to Tb2O[SeO3]2 with a “Lone—Pair” Channel Structure

Two new octahedral/pyramidal frameworks containing both cation channels and lone-pair channels: syntheses and structures of Ba2MnIIMn2III(SeO3)6 and PbFe2(SeO3)4

“…These related phases demonstrate a self-containment effect [4] in which the Se IV lone pairs of electrons are directed into otherwise empty, infinite, one-dimensional 8-ring channels of significant size. A similar effect has recently been demonstrated for the phase Tb 2 O(SeO 3 ) 2 , in which the selenite moieties arrange themselves so that their lone pairs occupy channels in a manner that reflects the4 symmetry of other parts of the structure [5].…”

“…Based on geometrical placement, the Se lone pairs are directed into these 8-ring channels. Unlike the case of Tb 2 O(SeO 3 ) 2 [5] there is no obvious symmetry relationship between the packing of the metalcentered octahedra and the Se lone pairs. The occurrence of lone-pair channels of reasonable size and redox-active Mn II /Mn III metal centers in Ba 2 Mn 3 (SeO 3 ) 6 suggests the possibility of redox intercalation in which a process schematically represented by Ba 2 Mn II Mn 2 III (SeO 3 ) 6 +Li-Li x Ba 2 Mn II 1+x Mn III 2Àx (SeO 3 ) 6 (0pxp2) could occur and we are now investigating this possibility further.…”

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

“…[SeO 3 ] 2− units in a 1:2 molar ratio according to M 2 O[SeO 3 ] 2 (Tb 2 O[SeO 3 ] 2 -type crystal structure [9]). With other additional anions, derivatives such as MF[SeO 3 ] (M = La) [10] and M 3 F[SeO 3 ] 4 (M = Nd, Sm, Gd, Dy) [11] in the case of F − or MCl[SeO 3 ] (M = Nd, Ho, Er) [12,13] with Cl − have been reported in the newer literature as the only examples of waterand/or hydrogen-free halide oxoselenates(IV) of the trivalent lanthanides obtained as single crystals.…”

“…in the monoclinic system (C2/m; a = 1229.13(9) pm, b = 546.17(4) pm, c = 978.79(7) pm, β = 90.485(6) • ; Z = 2) [16,19] and contains three crystallographically different Tb 3+ cations in seven-and eight-fold coordination of O 2− and Cl − anions, respectively. The crystal structure of Tb 5 O 4 Cl 3 [SeO 3 ] 2 is layered and built up of corrugated terbium-oxygen sheets 2 ∞ {[O 4 Tb 5 ] 7+ } formed by edge-and vertex-shared [OTb 4 ] 10+ tetrahedra spreading parallel to the (0 0 1) plane.…”

“…pm, c = 521.56(4) pm, Z = 4)[9] exhibits Tb 3+ cations in squareantiprismatic coordination of eight oxygen atoms. Six of these belong to six different isolated1 -tetrahedral [SeO 3 ] 2− anions, whereas the remaining two are not bonded to selenium at all.…”