Die Reihe der nicht-zentrosymmetrischen tetragonalen Lanthanoid(III)-Oxidoantimonat(III)-Chloride LnSb2O4Cl (Ln = Gd–Lu)

Abstract

Abstract 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.