The oxygen atoms of the two new compounds belong to ψ1-tetrahedral [SbO3]3− units, which are either vertex-connected to four-membered rings in YSb2O4Cl or to endless chains in YSb2O4Br. Eu3+- and Tb3+-doped samples show red or green luminescence.

All representatives of the isotypic series LnSb2O4Cl (Ln = Gd–Lu) could be obtained as single crystals, which crystallize just like the prototypic YSb2O4Cl in the non-centrosymmetric tetragonal space group P4212. The steady decrease in lattice parameters from a = 781.08(4) pm and c = 881.47(6) pm for GdSb2O4Cl to a = 764.66(4) pm and c = 877.53(7) pm for LuSb2O4Cl reflect the consequences of the lanthanide contraction, as expected. The Ln 3+ cations reside in the surrounding of eight oxygen atoms arranged as square hemiprisms [LnO8]13−, which are linked by four of their coplanar edges to form layers according to 2 ∞ { [ L n O 8 / 2 e ] 5 − } $\begin{array}{l}2\hfill \\ \infty \hfill \end{array}\left\{{\left[Ln{\text{O}}_{8/2}^{e}\right]}^{5-}\right\}$ parallel to the (001) plane. The Sb3+ cations form ψ1-tetrahedral [SbO3]3– anions together with three oxygen atoms. Two of these anions are connected with additional Sb3+ cations, but the third one shows no extra connectivity. Four ψ1-tetrahedral [SbO3]3– units build an eight-membered ring 0 ∞ { [ Sb 4 O 8 ] 4 − } $\begin{array}{l}0\hfill \\ \infty \hfill \end{array}\left\{{\left[{\text{Sb}}_{4}{\text{O}}_{8}\right]}^{4-}\right\}$ . These isolated rings are arranged parallel to the (001) plane. Between the oxygen-connected triple layers of Ln 3+ and Sb3+ cations with the composition 2 ∞ { [ L n Sb 2 O 4 ] + } $\begin{array}{l}2\hfill \\ \infty \hfill \end{array}\left\{{\left[Ln{\text{Sb}}_{2}{\text{O}}_{4}\right]}^{+}\right\}$ there are single layers of Cl− anions, not connected strongly to any of the trications. Due to the presence of isolated cyclic [Sb4O8]4– anions, these lanthanoid(III) oxidoantimonate(III) chlorides LnSb2O4Cl (Z = 4) can also be described with the molecular formula Ln 2[Sb4O8]Cl2 (Ln = Gd–Lu) for Z = 2.

Boryl-substituted phosphines NHB-P(R)Ph (R = H, Ph, NHB = N-heterocyclic boryl substituent) react with Fe 2 (CO) 9 to give isolable Fe(CO) 4 complexes, two of which were characterized by single-crystal XRD studies. The electronic and steric properties for a series of the boryl phosphines were further assessed by evaluation of TEPs for in-situ formed complexes [RhCl(NHB-PR 1 R 2 )(CO) 2 ] (R 1 , R 2 = H, Ph, Me, NMe 2 ), and calculations of buried volumes for Fe(CO) 4 complexes. The results imply that the NHB-phosphines exhibit due to their conforma- [a]

Dedicated to Professor Caroline Röhr on the Occasion of her 60th BirthdayThe two lanthanoid oxidoantimonate (III) chlorides SmSb 2 O 4 Cl and EuSb 2 O 4 Cl are accessible from solid-state reactions of Sb 2 O 3 with Ln 2 O 3 and LnCl 3 (Ln = Sm and Eu) at 750 °C for two days. They crystallize in the centrosymmetric tetragonal space group P4/ncc with the lattice parameters a = 787.13(4) pm, c = 1765.24(12) pm for SmSb 2 O 4 Cl and a = 783.56(4) pm, c = 1764.05(12) pm for EuSb 2 O 4 Cl with Z = 8. Both can also be described with the crystal-chemical formula Ln 2 [Sb 4 O 8 ]Cl 2 for Z = 4, since they comprise isolated [Sb 4 O 8 ] 4À rings. This structural motif has some very close similarities to the known series of non-centrosymmetric LnSb 2 O 4 Cl representatives (Ln = Gd-Lu), crystallizing in the tetragonal space group P42 1 2. All lanthanoid(III) cations have eight oxygen atoms as nearest neighbors arranged as square prisms [LnO 8 ] 13À , which are connected to layers by four parallel edges according to 2 ∞ f½LnO e8=2 � 5À g with fluorite-like topology. The Sb 3 + cations together with three oxygen atoms each and their lone-pair of electrons form ψ 1 -tetrahedra [SbO 3 ] 3À . Four of these [SbO 3 ] 3À entities join to 0 ∞ Sb 4 O 8 ½ � 4À f g rings with four bridging and four terminal oxygen atoms. Both centrosymmetric representatives, in contrast to the series of non-centrosymmetric ones, have a doubled lattice parameter c and several more symmetry elements, which will be discussed in detail.

EuScCuSe3 was synthesized from the elements for the first time by the method of cesium-iodide flux. The crystal belongs to the orthorhombic system (Cmcm) with the unit cell parameters a = 3.9883(3) Å, b = 13.2776(9) Å, c = 10.1728(7) Å, V = 538.70(7) Å3. Density functional (DFT) methods were used to study the crystal structure stability of EuScCuSe3 in the experimentally obtained Cmcm and the previously proposed Pnma space groups. It was shown that analysis of elastic properties as Raman and infrared spectroscopy are powerless for this particular task. The instability of EuScCuSe3 in space group Pnma space group is shown on the basis of phonon dispersion curve simulation. The EuScCuSe3 can be assigned to indirect wide-band gap semiconductors. It exhibits the properties of a soft ferromagnet at temperatures below 2 K.

It was possible to synthesize colorless single crystals of La5Cl3[SbO3]4 (block-shaped) as well as La2Sb12O19Br4 and LaSb12O19I4 (both needle-shaped), representing three new compounds from the system of lanthanum oxoantimonate(III) halides, which have not been described in the literature before. La5Cl3[SbO3]4 crystallizes in the monoclinic space group P2/c with the lattice parameters a = 895.82(5) pm, b = 564.28(3) pm, c = 1728.19(9) pm, and β = 90.007(2)° for Z = 2. This layered compound contains isolated ψ1-tetrahedral [SbO3]3– units, square hemiprisms [LaO8]13–, and antiprisms [LaO4Cl4]9−. La2Sb12O19Br4 and LaSb12O19I4 crystallize isotypically in the orthorhombic space group Pnma with a = 3184.69(19) pm, b = 417.78(3) pm, c = 1019.85(6) pm for the bromide and a = 3215.08(19) pm, b = 419.94(3) pm, c = 1062.89(6) pm for the iodide. Instead of isolated [SbO3]3− anions, semi-tubular features 1∞{[Sb12O19]2−} are present, which consist mainly of [SbO4]5− and few [SbO3]3− units with stereochemically active electronic lone pairs at their Sb3+ centers. Within these so-called “double-halfpipes”, La3+ is surrounded by nine oxygen atoms as [LaO9]15– polyhedron without any contact with X− anions. Single-crystal Raman measurements were performed for La5Cl3[SbO3]4 and LaSb12O19I4, and La5Cl3[SbO3]4 was structurally compared with the isostoichiometric, but not isotypic La5F3[SbO3]4.

The title compound, dicerium(III) oxidodisilicate, Ce2[Si2O7], was obtained as a by-product in its H-type structure after attempts to synthesize CeSb2O4Cl from fused silica ampoules. It crystallizes isotypically with H-La2[Si2O7]. The four crystallographically distinct CeIII cations form distorted square antiprisms, capped square antiprisms, and bicapped square antiprisms as coordination polyhedra consisting of oxygen atoms. Four crystallographically different silicon atoms recruit the centers of two different isolated [Si2O7]6– units.

This paper reports for the first time on the new laminar quaternary orthorhombic heterometallic quaternary tellurides SrLnCuTe3, the fabrication of which has been a challenge until this work. Data on the crystal structure of tellurides complete the series of quaternary strontium chalcogenides SrLnCuCh3 (Ch = S, Se, Te). Single crystals of the compounds were synthesized from the elements by the halogenide-flux method at 1070 K. The compounds are crystallizing in two space groups Pnma (Ln = Sm, Gd and Tb) and Cmcm (Ln = Dy–Tm and Lu). For SrSmCuTe3 (a = 11.4592(7), b = 4.3706(3), c = 14.4425(9) Å, space group: Pnma) with the largest lanthanoid cation, Sr2+ shows C.N. = 7, whereas Sm3+ reveals a diminished coordination number C.N. = 6. For SrLuCuTe3 (a = 4.3064(3), b = 14.3879(9), c = 11.1408(7) Å, space group: Cmcm) with the smallest lanthanoid cation, coordination numbers of six are realized for both high-charged cations (Sr2+ and Lu3+: C.N. = 6). The cations Sr2+, Ln3+, Cu+ each take independent positions. The structures are built by distorted [CuTe4]7– tetrahedra, forming the infinite chains {∞1[Cu(Te1)1/1t(Te2)1/1t(Te3)2/2e]5−} along [010] in SrLnCuTe3 (Ln = Sm, Gd and Tb) and [100] in SrLnCuTe3 (Ln = Dy–Tm and Lu). The distortion of the polyhedra [CuTe4]7– was compared for the whole series SrLnCuTe3 by means of τ4-descriptor for the four coordinating Te2– anions, which revealed a decrease in the degree of distortion with a decreasing radius at Ln3+. The distorted octahedra [LnTe6]9– form layers {∞2[Ln(Te1)2/2(Te2)2/2(Te3)2/2]3−}. The distorted octahedra and tetrahedra fuse to form parallel layers {∞2[CuLnTe3]2−} and between them, the Sr2+ cations providing three-dimensionality of the structure are located. In the SrLnCuTe3 (Ln = Sm, Gd and Tb) structures, the Sr2+ cations center capped the trigonal prisms [SrTe6+1]12−, united in infinite chains {∞1[Sr(Te1)2/2(Te2)3/3(Te3)2/2]4−} along the [100] direction. The domains of existence of the Ba2MnS3, BaLaCuS3, Eu2CuS3 and KZrCuS3 structure types are defined in the series of orthorhombic chalcogenides SrLnCuCh3 (Ch = S, Se and Te). The tellurides SrLnCuTe3 (Ln = Tb–Er) of both structure types in the temperature range from 2 up to 300 K are paramagnetic, without showing clear signs of a magnetic phase transition.