Sn5Ir6B2 und Sn4Ir7B3: Zinn-Iridiumboride mit eindimensionalen Ir/B-Verbänden

Sn₅Ir₆B₂ and Sn₄Ir₇B₃: Tin Iridiumborides with Onedimensional Ir/B Structural Elements Sn₅Ir₆B₂ (hexagonal, P6 2m, a = 658.97(5) pm, c = 559.19(3) pm, Z = 1, 391 reflexions, 16 parameters, R = 0.037) and Sn₄Ir₇B₃ (hexagonal, P6₃/m, a = 926.63(5) pm, c = 563.19(3) pm, Z = 2, 323 reflexions, 24 parameters, R = 0.045) were prepared by reaction of the elements. Their structures were determined by means of single crystal X-ray methods. The structure of Sn₅Ir₆B₂ may be derived from the Fe₂P type and contains columns of boron centered trigonal Ir prisms sharing their triangular faces. In the structure of Sn₄Ir₇B₃ six of these columns are connected to form a large column with hexagonal cross section. Only every second prism therein is occupied by a boron atom. In both structures these onedimensional Ir/B structural elements are embedded in a matrix of tin atoms composed of Sn-centered Sn₆ prisms twice as long as the Ir₆ prisms.     

Zn5Ir7B3, Zn5Rh7B3 und Zn7+xRh9–xB3 (x ≈ 0,4) – neue ternäre Zink‐Platinmetallboride

Zn₅Ir₇B₃, Zn₅Rh₇B₃, and Zn_7+xRh_9–xB₃ (x ≈ 0.4) – New Ternary Zinc Platinum Metal Borides The new ternary zinc borides Zn₅Ir₇B₃, Zn₅Rh₇B₃, and Zn_7+xRh_9–xB₃ (x ≈ 0.4) were prepared by reaction of the elemental components at temperatures in the range 1200 to 1230 ?C. They crystallize orthorhombically in the space group Pmma with Z = 2. Zn₅Ir₇B₃ (a = 1116.1(2) pm, b = 284.96(4) pm, c = 1178.1(2) pm; R = 0.042, 1414 reflections, 47 parameters) and Zn₅Rh₇B₃ (a = 1101.6(2) pm, b = 283.94(3) pm, c = 1166.6(4) pm, R = 0.033, 787 reflections, 47 parameters) are isotypic. Along the short axis planar nets of platinum metal atoms at y = 0 alternate with layers containing the boron and zinc atoms at z = ¹/₂. By the stacking of the platinum metal nets columns of trigonal prisms centered by boron atoms, columns of pentagonal prisms containing zinc atoms and channels with horse shoe shaped cross sections, all running along the b‐axis are formed. The latter are filled by an aggregation of zinc atoms consisting of four parallel rows. In the structure of Zn_7+xRh_9–xB₃ (a = 1117.1(3) pm, b = 285.38(8) pm, c = 1484.8(5) pm; R = 0.026, 975 reflections, 59 parameters) one of the sitesets is occupied by Rh and Zn atoms approximately in the ratio 6 : 4. The structure contains the same building elements as those found in Zn₅Rh₇B₃ and in addition Rh prisms with elongated hexagon cross sections accommodating pairs of zinc atoms. These prisms are connected by common faces to form layers perpendicular to the c axis.     

Zn11Rh18B8 and Zn10MRh18B8 with M = Sc,Ti, V,Cr, Mn,Fe, Co,Ni, Cu,Al, Si,Ge, Sn – New Ternary and Quaternary Zinc Rhodium Borides

Zn₁₁Rh₁₈B₈ and Zn₁₀MRh₁₈B₈ with M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, Si, Ge and Sn are obtained by reaction of the elemental components in sealed tantalum tubes at 1500 K. They crystallize tetragonally with Z = 2 in the spacegroup P4/mbm with lattice constants a = 1771.2(2) pm, c = 286.40(4) pm for Zn₁₁Rh₁₈B₈ and in the range a = 1767.65(9) pm, c = 285.96(3) pm (Zn₁₀NiRh₁₈B₈) to a = 1774.04(9) pm, c = 286.79(2) pm (Zn₁₀SnRh₁₈B₈) for the quaternary compounds. According to powder photographs all compounds are isotypic. Struture determinations based on single crystal X-ray data were performed with Zn₁₁Rh₁₈B₈, Zn₁₀FeRh₁₈B₈ and Zn₁₀NiRh₁₈B₈. The structure of Zn₁₁Rh₁₈B₈ is related to the Ti₃Co₅B₂ type. Along the short axis planar nets of rhodium atoms composed of triangles, squares, pentagons and elongated hexagons alternate with layers containing the boron and zinc atoms. The rhodium atoms form trigonal prisms centered by boron atoms, two kinds of tetragonal and pentagonal prisms centered by zinc atoms and elongated hexagonal prisms containing pairs of zinc atoms. In the quaternary compounds Zn₁₀MRh₁₈B₈ the zinc atoms in one sort of tetragonal prisms are replaced by M atoms.     

Das Kupfer–Iridiumborid Cu2Ir4B3 mit einer vom ZnIr4B3‐Typ abgeleiteten Schichtstruktur

The Copper Iridium Boride Cu₂Ir₄B₃ with a Layer Structure Derived from the ZnIr₄B₃ Type The new compound Cu₂Ir₄B₃ (orthorhombic, Cmcm, a = 283.21(2) pm, b = 2540.6(1) pm, c = 281.06(2) pm, Z = 2, 209 reflexions, 18 parameters, R = 0.043) was prepared by reaction of the elements. The structure is related to the ZnIr₄B₃ type. It contains slabs composed of Ir₆B‐ und Ir₆‐prisms which alternate with copper double layers.     

Synthese und Kristallstrukturen des Zink‐Rhodiumborids Zn5Rh8B4 und der Lithium‐ Magnesium‐Rhodiumboride LixMg5−xRh8B4 (x = 1.1 und 0.5) und Li8Mg4Rh19B12

Synthesis and Crystal Structures of Zinc Rhodium Boride Zn₅Rh₈B₄ and the Lithium Magnesium Rhodium Borides Li_xMg_5?xRh₈B₄ (x = 1.1 and 0.5) and Li₈Mg₄Rh₁₉B₁₂ The title compounds were prepared by reaction of the elemental components in metal ampoules under argon atmosphere (1100 °C, 7 d). In the case of Zn₅Rh₈B₄ (orthorhombic, space group Cmmm, a = 8.467(2) Å, b = 16.787(3) Å, c = 2.846(1) Å, Z = 2) a BN crucible enclosed in a sealed tantalum container was used. The syntheses of Li_xMg_5?xRh₈B₄ (orthorhombic, space group Cmmm, Z = 2, isotypic with Zn₅Rh₈B₄, lattice constants for x = 1.1: a = 8.511(3) Å, b = 16.588(6) Å, c = 2.885(1) Å, and for x = 0.5: a = 8.613(1) Å, b = 16.949(3) Å, c = 2.9139(2) Å) and Li₈Mg₄Rh₁₉B₁₂ (orthorhombic, space group Pbam, a = 26.210(5) Å, b = 13.612(4) Å, c = 2.8530(5) Å, Z = 2) were carried out in tantalum crucibles enclosed in steel containers using lithium as a metal flux. The crystal structures were solved from single crystal X‐ray diffraction data. In both structures Rh atoms reside at z = 0 and all non‐transition metal atoms at z = 1/2. Columns of Rh₆B trigonal prisms running along the c‐axis are laterally connected to form three‐dimensional networks with channels of various cross sections containing Li‐, Mg‐, and Zn‐atoms, respectively. A very short Li‐Li distance of 2.29(7) Å is observed in Li₈Mg₄Rh₁₉B₁₂.     

Phasenbeziehungen im System LiGa?Sn und die Kristallstrukturen der intermediären Phasen LiGaSn und Li2Ga2Sn

Phase Relations in the System LiGa? Sn and the Crystal Structures of the Intermediate Compounds LiGaSn and Li₂Ga₂Sn The quasibinary system LiGa? Sn contains the intermediate ternary phases Li₇Ga₇Sn₃, Li₂Ga₂Sn, Li₅Ga₅Sn₃, Li₃Ga₃Sn₂ and LiGaSn. Single crystals of LiGaSn (a = 632.9(4) pm, Fd3m, Z = 4), Li₃Ga₃Sn₂ (a = 445.4(3), c = 1 090.0(2) pm, hP*), Li₅Ga₅Sn₃ (a = 447.0(4), c = 4 220.0(9) pm, hP*) and Li₂Ga₂Sn (a = 441.1(2), c = 2 164.5(7) pm, P6₃/mmc, Z = 4) have been grown from the melt. The crystal structures of LiGaSn and Li₂Ga₂Sn have been determined by single crystal X-ray methods (R = 0.029 bzw. 0.107 respectively). The crystal structure of LiGaSn contains a sphalerite-type Ga/Sn-arrangement, the Ga/Sn-arrangement of Li₂Ga₂Sn corresponds to a stacking variant of the wurtzite- and sphalerite-type. The compounds can be classified in terms of the Zintl concept.     

Synthese und Struktur der Nitridoborat‐Nitride Ln4(B2N4)N (Ln = La,Ce) des Formeltyps Ln3+x(B2N4)Nx (x = 0, 1, 2)

Synthesis and Structure of Nitridoborate Nitrides Ln₄(B₂N₄)N (Ln = La, Ce) of the Formula Type Ln_3+x(B₂N₄)N_x (x = 0, 1, 2) The missing member of the formula type Ln_3+x(B₂N₄)N_x with x = 1 was synthesized and characterized for Ln = La and Ce. According to the single‐crystal X‐ray structure solution Ce₄(B₂N₄)N crystallizes in the space group C2/m (Z = 2) with the lattice parameters a = 1238.2(1) pm, b = 357.32(3) pm, c = 905.21(7) pm and β = 129.700(1)°. The anisotropic structure refinement converged at R1 = 0.039 and wR2 = 0.099 for all independent reflections. A powder pattern of La₄(B₂N₄)N was indexed isotypically with a = 1260.4(1) pm, b = 366.15(3) pm, c = 919.8(1) pm and β = 129.727(6)°. A structure rational for nitridoborates and nitridoborate nitrides containing B₂N₄ ions with the general formula Ln_3+x(B₂N₄)N_x with x = 0, 1, 2 is presented.     

The Ternary Stannides MgRuSn4 and MgxRh3Sn7—x (x = 0.98—1.55)

The magnesium transition metal stannides MgRuSn₄ and Mg_xRh₃Sn_7—x (x = 0.98—1.55) were synthesized from the elements in glassy carbon crucibles in a water‐cooled sample chamber of a high‐frequency furnace. They were characterized by X‐ray diffraction on powders and single crystals. MgRuSn₄ adopts an ordered PdGa₅ type structure: I4/mcm, a = 674.7(1), c = 1118.1(2) pm, wR2 = 0.0506, 515 F² values and 12 variable parameters. The ruthenium atoms have a square‐antiprismatic tin coordination with Ru—Sn distances of 284 pm. These [RuSn_8/2] antiprisms are condensed via common faces forming two‐dimensional networks. The magnesium atoms fill square‐prismatic cavities between adjacent [RuSn₄] layers with Mg—Sn distances of 299 pm. The rhodium based stannides Mg_xRh₃Sn_7—x crystallize with the cubic Ir₃Ge₇ type structure, space groupe Im3m. The structures of four single crystals with x = 0.98, 1.17, 1.36, and 1.55 have been refined from X‐ray diffractometer data. With increasing tin substitution the a lattice parameter decreases from 932.3(1) pm for x = 0.98 to 929.49(6) pm for x = 1.55. The rhodium atoms have a square antiprismatic tin/magnesium coordination. Mixed Sn/Mg occupancies have been observed for both tin sites but to a larger extend for the 12d Sn2 site. Chemical bonding in MgRuSn₄ and Mg_xRh₃Sn_7—x is briefly discussed.     

Anionische Fragmente aus h‐BN in der Struktur La6B4N10

Anionic Fragments of h‐BN in the Structure La₆B₄N₁₀ The compound La₆B₄N₁₀ was synthesized by solid state reactions at high temperatures. Crystals obtained for La₆B₄N₁₀ were systematically twinned and showed orthorhombic symmetry. An X‐ray crystal structure refinement on a needle shaped pseudo‐merohedral twin yielded the monoclinic space group P2₁/c, Z = 2, lattice parameters a = 971.89(6) pm, b = 1479.41(9) pm, c = 762.32(4) pm, β = 90.005(9)° and converged at R1 = 0.0352, wR2 = 0.0555 for all independent reflections. The structure of La₆(B₃N₆)(BN₃)N contains cyclic B₃N₆ ions with three exocyclic N atoms, carbonate ion like BN₃ units and nitride ions that can be considered as fragments or products of a nitration reaction of hexagonal boron nitride.     

Einkristalluntersuchungen an LiMF6 (M = Rh,Ir), Li2RhF6 und K2IrF6

Single Crystal Investigations on LiMF₆ (M = Rh, Ir), Li₂RhF₆, and K₂IrF₆ LiRhF₆, LiIrF₆, Li₂RhF₆, and K₂IrF₆ were obtained again, but for the first time investigated by single crystal X‐ray methods. Rubyred LiRhF₆ and yellow LiIrF₆ crystallize isostructural in the trigonal space group R3 – C²_3i (Nr. 148) with the lattice parameters LiRhF₆: a = 502.018(7) pm, c = 1355.88(3) pm, Z = 3 and d(Rh–F) = 185.5(1) pm; LiIrF₆: a = 506.148(4) pm, c = 1362.60(2) pm, Z = 3, d(Ir–F) = 187.5(3) pm (LiSbF₆‐Typ). Yellow Li₂RhF₆ crystallizes tetragonal in the space group P4₂/mnm – D¹⁴_4h (Nr. 136) with a = 463.880(8) pm, c = 905.57(2) pm, Z = 2 and d(Rh–F) = 190.3(4)–191.4(3) pm (Trirutil‐Typ). Yellow K₂IrF₆ crystallizes trigonal in the space group P3m1 – D³_3d (Nr. 164) with a = 578.88(7) pm, c = 465.06(5) pm, Z = 1 and d(Ir–F) = 194.0(6) pm, isotypic with K₂GeF₆.     

Ein grünes,paramagnetisches Goldfluorid – Sn1−xAuxF4?

A Green Paramagnetic Gold Fluoride – Sn_1?xAu_xF₄? Green single crystals were obtained by heating (Au-tube, 450° – 500°C) a mixture of SnF₂ and AuF₃ (Sn : Au = 1 : 1) which correspond to the SnF₄-type [2, 3] (two single crystals, A: 762 I_o, R1 = 2.4%; B: 1591 I_o, R1 = 1.2% (SHELXL-93); I4/mmm (No. 139); B: a = 404.8(1) pm, c = 796.4(1) pm, c/a = 1.97, Z_F2 = 0.2354). Due to atom absorption and Mössbauer measurements the crystals contain Au. The compound is paramagnetic and follows the Curie-Weiß law (14.7–251.3 K, θ = ?12 K, μ/μ_B = 1.55). ESR-experiments confirm that Au is surrounded by 6 F^? according to Sn in SnF₄ (2 short (187.5 pm) and 4 longer (202.4 pm) distances). The observed Mössbauer spectra could not be interpreted yet, but they don't correspond to any known.     

Synthese,Struktur und Eigenschaften von [(C4H9)2NH2]4[Sn2Se6], [(C4H9)2NH2]4[Sn4Se10] · 2 H2O und [(C3H7)3NH]2[Sn3Se7]

About Selenidostannates. I Synthesis, Structure, and Properties of [Sn₂Se₆]^4–, [Sn₄Se₁₀]^4–, and [Sn₃Se₇]^2– The selenidostannates [(C₄H₉)₂NH₂]₄Sn₂Se₆ · H₂O ( I ), [(C₄H₉)₂NH₂]₄Sn₄Se₁₀ · 2 H₂O ( II ) und [(C₃H₇)₃NH]₂Sn₃Se₇ ( III ) were prepared by hydrothermal syntheses from the elements and the amines. I crystallizes in the monoclinic spacegroup P2₁/n (a = 1262.9(3) pm, b = 1851.3(4) pm, c = 2305.2(4) pm, β = 104.13(3)° and Z = 4). The [Sn₂Se₆]^4– anion consists of two edge‐sharing tetrahedra. II crystallizes in the orthorhombic spacegroup Pna2₁ (a = 2080.3(4) pm, b = 1308.2(3) pm, c = 2263.5(5) pm and Z = 4). The anion is formed from four SnSe₄ tetrahedra which are joined by common corners to the adamantane cage [Sn₄Se₁₀]^4–. III crystallizes in the orthorhombic spacegroup Pbcn (a = 1371.1(3) pm, b = 2285.4(5) pm, c = 2194.7(4) pm and Z = 8). The anion is a chain, built from edge‐sharing [Sn₃Se₅Se_4/2]^2– units, in which two corner sharing tetrahedra are connected to a trigonal bipyramid by an edge of one and a corner of the other tetrahedron. The results of the TG/DSC measurements and of temperature dependent X‐ray diffractograms reveal that I and II decompose at first by release of minor quantities of triethylammonium to compounds with layer structure and larger cell dimensions. At still higher temperature the rest of triethylammonium and H₂Se is evolved, leaving SnSe₂ and Se in the bulk. The former decomposes partially at the highest temperature to SnSe. In the measurements of III the complex intermediate compound was not observed. III decomposes directly to SnSe₂.     

Hydroxoverbindungen. 10. Über die Natriumoxohydroxostannate(II) Na4[Sn4O(OH)10] und Na2[Sn2O(OH)4]

Hydroxo Compounds. 10. The Sodium Oxohydroxostannates(II) Na₄[Sn₄O(OH)₁₀] and Na₂[Sn₂O(OH)₄] Na₄[Sn₄O(OH)₁₀] = Na₄[Sn(OH)₃]₂[Sn₂O(OH)₄] ( I ) and Na₂[Sn₂O(OH)₄] ( II ) have now been doubtlessly characterized as the first Na-hydroxostannates(II). I crystallizes monoclinic in P2₁/n (a = 1522.4(5) pm, b = 830.0(2) pm, c = 1276.0(3) pm, β = 104.8(2)°, Z = 4, R = 0.047, 1137 I_hkl); II crystallizes orthorhombic in P2₁2₁2₁ (a = 1450(2) pm, b = 1665(2) pm, c = 590.7(8) pm, Z = 8, R = 0.042, 1208 I_hkl). II is identical with the compound which was described up to now as “Na[Sn(OH)₃]”. The new compounds contain the complex anions [Sn(OH)₃]^? and [Sn₂O(OH)₄]^2?, whose structures are now proved. The oxotetrahydroxo-distannate(II) anion [Sn₂O(OH)₄]^2? exhibits a syn-conformation with respect to the projection along the (Sn? Sn) vector. The two compounds crystallize with pronounced layer structures, which show direct topotactical relations with one another as well as with SnO. This relates closely to the fast formation of SnO from crystals of I and II .     

Etude Structurale de la forme basse Température de NH4Sn2F5 (Type γ)

Structural Study of the Low-temperature Modification of NH₄Sn₂F₅ (Type γ) NH₄Sn₂F₅, monoclinic, space group C2, Cm or C2/m, a = 7.361(4) Å, b = 12.752(6) Å, c = 10.492(5) Å, β = 103.5(7)°, V = 957,2(9) ų, Z = 6. MoKα (= 0.7107 Å) R = 0.036 for 476 observed reflexions. The structure is built from alternative layers [Sn? F] and [NH₄⁺]. Three kinds of fluorine have vacancy positions, that explains the bidimensional conduction in NH₄Sn₂F₅.     

Zur Kenntnis von Tripraseodym‐hexanitridotriborat Pr3B3N6: Neue Synthese und Verfeinerung der Kristallstruktur

On Tripraseodymium Hexanitridotriborate Pr₃B₃N₆: New Synthesis and Crystal Structure Refinement Single‐crystalline Pr₃B₃N₆ was obtained by the reaction of praseodymium and BN_x(NH)_y(NH₂)_z in a NaCl melt under N₂ atmosphere in a high‐frequency furnace at 1250 °C. Contrary to literature data, Pr₃B₃N₆ crystallizes in the centrosymmetric space group R 3 c as revealed by single‐crystal X‐ray diffraction (a = 1211.95(9), c = 701.53(7) pm, Z = 6, R1 = 0.0258, wR2 = 0.0658). In the solid, Pr₃B₃N₆ contains Pr³⁺ and planar cyclotrinitridoborate units B₃N₆^9–. The anions represent motifs from the structure of hexagonal boron nitride (h‐BN) and they are stacked analogously along [001]. Both the bond lengths B–N (average value 147.8 pm) and the interionic distances between the anions (350.8 pm) are comparable with the values in h‐BN.     

Alkaline Metal Stannide‐Stannates: ‘Double Salts’ with Zintl Sn and Stannate SnO Anions

Using the reduction of tin oxides with the elemental alkaline metals rubidium and cesium, stannide stannates have been synthesized which contain Zintl anions [Sn₄]^4— (i.e. Sn^—I) and isolated oxostannate ions [SnO₃]^4— (i.e. Sn^+II) together with further oxide ions for charge compensation. The crystal structures of the three compounds A_23.6Sn_7.4O_13.2 = A_23.6[Sn₄][SnO₃]_3.4[O]₃ (A = Rb 1a : monoclinic, P2₁/c, a = 2174.2(6), b = 1137.0(6), c = 2373.6(6) pm, β = 116.11(2)°, Z = 4, R1 = 0.056; A = Cs 1b : monoclinic, P2₁/c, a = 2042.6(6), b = 1185.4(3), c = 2481.1(7) pm, β = 97.06(2)°, Z = 4, R1 = 0.075) and Cs₄₈Sn₂₀O₂₁ = Cs₄₈[Sn₄]₄[SnO₃]₄[O]₇[O₂] ( 2 monoclinic, P2/c, a = 1701.8(3), b = 877.4(2), c = 4556.9(7) pm, β= 101.47(1)°, R1 = 0.093) have been determined on the basis of single crystal data. The transparency of the compounds allowed the recording of raman spectra of the anion [Sn₄]^4—. The ¹¹⁹Sn Moessbauer spectrum of the rubidium compound shows a singulet in good agreement with RbSn, overlapping a doublet caused by Sn²⁺ in the asymmetrical environment of the strongly electronegative oxygen ligands of SnO.     

Ein neues Syntheseverfahren für die Wolframbronze Cs0,29WO3

A Novel Synthetic Access to the Tungsten Bronze Cs_0.29WO₃ and its Crystal Structure The hexagonal tungsten bronze Cs_0.29WO₃ was obtained in form of black, prismatic crystal by the reduction of WO₃ with molten cesium iodide at 700°C. Its crystal structure was determined by X-ray diffraction (399 unique observed reflexions, R = 0.058). Crystal data: a = 741.2(3), c = 760.0(5) pm, space group P6₃22, Z = 6. It corresponds to the known structure of hexagonal tungsten bronzes, having tungsten atoms displaced from the octahedra centres by 11.9 pm and with three different W? O bond lengths (198, 191, 187 pm). The WO₆ octahedra are slightly titled mutually.     

Ternary Rhodium Borides A3Rh5B2 (A = Mg,Sc) and Quaternary Derivatives A2MRh5B2. Preparation,Crystal Structure (M = Main Group and 3 d Elements), and Magnetism (M = Mn,Fe)

The new ternary rhodium borides Mg₃Rh₅B₂ and Sc₃Rh₅B₂ (P4/mbm, Z = 2; a = 943.4(1) pm, c = 292.2(1) pm and a = 943.2(1) pm, c = 308.7(1) pm, respectively) crystallize with the Ti₃Co₅B₂ type structure. Mg and Sc may in part be substituted by a variety of elements M. For M = Si and Fe, homogeneity ranges were found according to A_3–xM_xRh₅B₂ with 0 ≤ x ≤ 1.0 for A = Sc and with x up to 1.5 for A = Mg. Quaternary compounds with x = 1 (A₂MRh₅B₂: A/M in short) were prepared with M = Be, Al, Si, P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Sn (Co, Ni only with A = Mg; Sn only with A = Sc; P, As with deficiencies). Single crystal X‐ray investigations show an ordered substitutional variant of the Ti₃Co₅B₂ type in which the M atoms are arranged in chains along [001] with intrachain and interchain M–M distances of about 300 pm and 660 pm, respectively. Measuring the magnetisation (1.7 K–800 K) of the phases Mg/Mn, Sc/Mn, Mg/Fe, and Sc/Fe reveals antiferromagnetic interactions in the first and dominating ferromagnetic intrachain interactions in the remaining ones. Interchain interactions of antiferromagnetic nature are evident in Sc/Mn and Mg/Fe leading to metamagnetism below T_N = 130 K, while Sc/Fe behaves ferromagnetically below T_C = 450 K. The overall trend towards stronger ferromagnetic interactions with increasing valence electron concentration is obvious.     

Crystal Structures and Raman Spectra of cis‐[SnCl4(H2O)2]·2H2O,cis‐[SnCl4(H2O)2]·3H2O, [Sn2Cl6(OH)2(H2O)2]·4H2O,and [HL][SnCl5(H2O)]·2.5H2O (L=3‐acetyl‐5‐benzyl‐1‐phenyl‐4, 5‐dihydro‐1, 2, 4‐triazine‐6‐one oxime,C18H18N4O2)

The complexes cis‐[SnCl₄(H₂O)₂]·2H₂O ( 1 ), [Sn₂Cl₆(OH)₂(H₂O)₂]·4H₂O ( 3 ), and [HL][SnCl₅(H₂O)]·2.5H₂O ( 4 ) were isolated from a CH₂Cl₂ solution of equimolar amounts of SnCl₄ and the ligand L (L=3‐acetyl‐5‐benzyl‐1‐phenyl‐4, 5‐dihydro‐1, 2, 4‐triazine‐6‐one oxime, C₁₈H₁₈N₄O₂) in the presence of moisture. 1 crystallizes in the monoclinic space group Cc with a = 2402.5(1) pm, b = 672.80(4) pm, c = 1162.93(6) pm, β = 93.787(6)° and Z = 8. 4 was found to crystallize monoclinic in the space group P2₁, with lattice parameters a = 967.38(5) pm, b = 1101.03(6) pm, c = 1258.11(6) pm, β = 98.826(6)° and Z = 2. The cell data for the reinvestigated structures are: [SnCl₄(H₂O)₂]·3H₂O ( 2 ): a = 1227.0(2) pm, b = 994.8(1) pm, c = 864.0(1) pm, β = 103.86(1)°, with space group C2/c and Z = 4; 3 : a = 961.54(16) pm, b = 646.29(7) pm, c = 1248.25(20) pm, β = 92.75(1)°, space group P2₁/c and Z = 4.     

Einkristallstrukturuntersuchungen an hexagonalen Fluorperowskiten AMIIF3 (MII = Mg,Mn, Fe,Co, Ni)

Single Crystal Structural Studies at Hexagonal Fluoride Perovskites AM^IIF₃ (M^II = Mg, Mn, Fe, Co, Ni) At single crystals of nine fluoride phases AMF₃ the hexagonal perovskite structures were refined by X‐ray methods, of RbNiF₃ below T_C £ 145 K, too. The hexagonal 6 L type (P6₃/mmc, Z = 6) is found at: RbMgF₃ (a = 585.7(1); c = 1426.0(1) pm), CsMnF₃ (624.4(1); 1515.4(4) pm), CsFeF₃ (616.8(1); 1488.4(6) pm), Rb_0.63Cs_0.37CoF₃ (599.1(1); 1460.3(4) pm), RbNiF₃ (128 K: 582.6(1); 1426.4(6) pm), Cs₂BaLiNi₂F₉ (593.1(1); 1447.1(4) pm). Of the hexagonal‐rhombohedral 9 L type (R 3 m, Z = 9) are CsCoF₃ (620.1(1); 2264.0(7) pm) and yellow CsNiF₃ (614.7(1); 2235.3(6) pm), prepared at lower temperatures resp. under high pressure, whereas light green CsNiF₃ (625.5(1); 524.2(1) pm) belongs to the 2 L type (P6₃/mmc, Z = 2). The occurence of these structures and the interatomic distances observed, comparing also normal and high pressure phases, are discussed in connection with the tolerance factor.