The First Alkali‐Metal Lanthanoid(III) Iodide Oxotellurate(IV): Na 2 Lu 3 I 3 [TeO 3 ] 4

Colorless platelets of Na 2 Lu 3 I 3 [TeO 3 ] 4 were obtained within five days at 775 °C by the reaction of Lu 2 O 3 and TeO 2 in a 3:8 molar ratio with NaI added in excess as both fluxing agent and reactant in evacuated silica ampoules. It crystallizes in the monoclinic space group P 2/ c with the lattice parameters a = 921.69(5), b = 552.71(3), c = 1664.37(9) pm, β = 90.218(4)° and Z = 2. The crystal structure of Na 2 Lu 3 I 3 [TeO 3 ] 4 exhibits two crystallographically different Lu 3+ cations, both coordinated by eight O 2– anions as square antiprisms. These polyhedra are interconnected through four common edges to build up {}^2_∞ {[LuO {}^e_8/2 ] 5– } layers (e = edge‐linking) parallel to (100). Furthermore, the crystal structure includes a crystallographically unique Na + cation surrounded by four O 2– and four I – anions also in the shape of a square antiprism. These polyhedra connect via common (I2) – ···(I2) – edges in generating {}^1_∞ {[Na 2 O 8 I {}^e_4 ] 18– } double‐strands that are further linked by (I1) – vertices to result in the formation of {}^2_∞ {[Na 2 O 8 I 3 {}^e,v_3 ] 17– } layers (v = vertex‐linking) spreading out parallel to (100) as well. Thus, the crystal structure contains two crystallographically distinct I – anions, of which (I1) – is coordinated nearly linear (∢ (Na–I1–Na) = 179.6°) by two Na + cations, whereas (I2) – has contact to three of them displaying a distance of 114 pm from the triangular (Na + ) 3 plane. The crystal structure of Na 2 Lu 3 I 3 [TeO 3 ] 4 is completed by two crystallographically independent Te 4+ cations that show stereochemically active non ‐bonding electron pairs (“ lone pairs ”) and are located above and below the {}^2_∞ {[LuO {}^e_8/2 ] 5– } layers forming isolated ψ 1 ‐tetrahedral [TeO 3 ] 2– anions ( d (Te–O) = 188–190 pm) with all oxygen atoms.