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.