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.     

Die Seltenerdmetallpolyselenide Gd8Se15, Tb8Se15−x,Dy8Se15−x,Ho8Se15−x,Er8Se15−x und Y8Se15−x (0 < x ≤ 0.3) – Zunehmende Fehlordnung in ausgedünnten,planaren Selenschichten

The Rare Earth Metal Polyselenides Gd₈Se₁₅, Tb₈Se_15?x, Dy₈Se_15?x, Ho₈Se_15?x, Er₈Se_15?x, and Y₈Se_15?x – Increasing Disorder in Defective Planar Selenium Layers Single crystals of the rare earth metal polyselenides Gd₈Se₁₅, Tb₈Se_15?x, Dy₈Se_15?x, Ho₈Se_15?x, Er₈Se_15?x, and Y₈Se_15?x (0 < x ≤ 0.3) have been prepared by chemical transport reactions (1120 K→ 970 K, 14 days, I₂ as carrier) starting from pre‐annealed powders of nominal compositions between LnSe₂ and LnSe_1.9. The isostructural title compounds adopt a 3 × 4 × 2 superstructure of the ZrSSi type and can be described in space group Amm2 with lattice parameters of a = 12.161(1) Å, b = 16.212(2) Å and c = 16.631(2) Å (Gd₈Se₁₅), a = 12.094(2) Å, b = 16.123(2) Å and c = 16.550(2) Å (Tb₈Se_15?x), a = 12.036(2) Å, b = 16.060(2) Å and c = 16.475(2) Å (Dy₈Se_15?x), a = 11.993(2) Å, b = 15.999(2) Å and c = 16.471(2) Å (Ho₈Se_15?x), a = 11.908(2) Å, b = 15.921(2) Å and c = 16.428(2) Å (Er₈Se_15?x), and a = 12.045(2) Å, b = 16.072(3) Å and c = 16.626(3) Å (Y₈Se_15?x), respectively. The structure consists of puckered [LnSe] double slabs and planar Se layers alternating along [001]. The planar Se layers contain a disordered arrangement of dimers, Se^2? and vacancies. All compounds are semiconducting and contain trivalent rare earth metals (Ln³⁺).     

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.     

Intermetallic Phases in the Ca‐Cu‐Sn System

Twelve ternary alloys in the Ca‐Cu‐Sn system were synthesized as a test on the existing phases. They were prepared from the elements sealed under argon in Ta crucibles, melted in an induction furnace and annealed at 700 °C or 600 °C. Four ordered compounds were found: CaCuSn (YbAuSn type), Imm2, a = 4.597(1) Å, b = 22.027(2) Å, c = 7.939(1) Å, Z = 12, wR2 = 0.080, 1683 F² values; Ca₃Cu₈Sn₄ (Nd₃Co₈Sn₄ type), P6₃mc, a = 9.125(1) Å, c = 7.728(1) Å, Z = 2, wR2 = 0.087, 704 F² values; CaCu₂Sn₂ (new structure type), C2/m, a = 10.943(3) Å, b = 4.222(1) Å, c = 4.834(1) Å, β = 107.94(1)°, Z = 2, wR2 = 0.051, 343 F² values; CaCu₉Sn₄ (LaFe₉Si₄ type), I4/mcm, a = 8.630(1) Å, c = 12.402(1) Å, Z = 4, wR2 = 0.047, 566 F² values. In all phases the shortest Cu‐Sn distances are in the range 2.59‐2.66Å, while the shortest Cu‐Cu distances are practically the same, 2.53‐2.54Å, except CaCuSn where no Cu‐Cu contacts occur.     

Novel Derivatives of the CaIn2 Type of Structure: Yb1+xMg1—xGa4 (0 ≤ x ≤ 0.058) and YLiGa4

The compounds Yb_1+xMg_1—xGa₄ (0 ≤ x ≤ 0.058) and YLiGa₄ were synthesized by direct reaction of the elements in sealed niobium crucibles. The atomic arrangement of Yb_1+xMg_1—xGa₄ (x = 0.058) represents a new structure type (space group P6¯m2, a = 4.3979(3)Å and c = 6.9671(7)Å) as evidenced by single crystal structure analysis and can be described as an ordered variant of CaIn₂. YLiGa₄ is isotypic to the ytterbium compound according to X‐ray Guinier powder data (a = 4.3168(1)Å and c = 6.8716(2)Å). Measurements of the magnetic susceptibility of both compounds reveal intrinsic diamagnetic behaviour, i.e., ytterbium in the 4f¹⁴ configuration for Yb_1+xMg_1—xGa₄ (x = 0). From electrical resistivity data both compounds can be classified as metals. The compressibility of Yb_1+xMg_1—xGa₄ (x = 0.058) as measured in diamond anvil cells by angle‐dispersive X‐ray diffraction is compatible with a valence change of the ytterbium atoms at high‐pressures and indicates a slight anisotropy which is in accordance with the structural organisation of the gallium network. X‐ray absorption spectra of the Yb L_III edge of Yb_1+xMg_1—xGa₄ (x = 0.058) at pressures up to 25.0 GPa show a two‐peak structure which reveals the presence of Yb in the 4f¹⁴ and 4f¹³ states. The amount of ytterbium in the 4f¹³ state increases in two steps with progressing compression. The bonding analysis by means of the electron localization function reveals the Zintl‐like character of both compounds and confirms the 4f¹⁴ state for the majority of ytterbium atoms.     

Homologous Silver Bismuth Chalcogenide Halides (N,x)P. II. The (2, x)P and (3, x)P Structure Families of Modular Compounds with Tunable Composition and Structure

The crystal structures of two members of the solid solution series Ag_3xBi_5?3xS_8?6xCl_6x?1 (x = 0.52 (I) , x = 0.67 (II) ) and three compounds of the Ag_4xBi_6?4xQ_10?8xBr_8x?2 series (Q = S: x = 0.70 (III) , x = 0.84 (IV) ; Q = Se: x = 0.72 (V) ) were determined by single‐crystal X‐ray diffraction. The compounds crystallize in the monoclinic space group C2/m (No. 12) with a = 1326.7(3), b = 403.9(1), c = 1176.7(2) pm, β = 107.83(3)° for (I) ; a = 1325.4(3), b = 403.3(1), c = 1170.6(2) pm, β = 108.14(3)° for (II) ; a = 1338.9(4), b = 407.7(1), c = 1426.4(4) pm, β = 113.95(2)° for (III) ; a = 1346.7(4), b = 409.3(1), c = 1440.7(4) pm, β = 114.40(1)° for (IV) ; and a = 1370.9(2), b = 417.64(4), c = 1480.4(2) pm, β = 114.92(2)° for (V) . (I) and (II) adopt the PbBi₄S₇ structure type, (III) to (V) crystallize in the CuBi₅S₈ type. All five compounds belong to the homologous series with general formula [BiQX]₂[Ag_xBi_1?xQ_2?2xX_2x?1]_N+1 (Q = S, Se; X = Cl, Br; 1/2 ≤ x ≤ 1)), which resemble minerals of the pavonite series. They are characterized by the parameters N and x and are denoted ^{(N, x)}P. In the crystal structures, two kinds of layered modules alternate along [001]. Modules of type A uniformly consist of paired rods of face‐sharing monocapped trigonal prisms around Bi atoms with octahedra around mixed occupied metal positions (M = Ag/Bi) between them. Modules of type B are composed of chains of edge‐sharing [MZ₆] octahedra (M = Ag/Bi; Z = Q/X). These NaCl‐type fragments are of thickness N = 2 in Ag_3xBi_5?3xS_8?6xCl_6x?1 and N = 3 in Ag_4xBi_6?4xQ_10?8xBr_8x?2. All structures exhibit Ag/Bi disorder in octahedrally coordinated metal positions and Q/X mixed occupation of some anion positions.     

The Crystal Structure of Kx(MgxIn1–x)F3 (x = 0.38): a New Magnéli‐Bronze Type Fluoride

K_x(Mg_xIn_1–x)F₃ (x = 0.38) is monoclinic, pseudo tetragonal: a = 12.781(2) Å, b = 12.787(2) Å, c = 7.930(1) Å, β = 90,00(1)°, Z = 20. The crystal structure was solved in the space group P2₁/a (No. 14), subgroup of the tetragonal space group P4/mbm (No. 127), from X‐ray single crystal data using 4302 unique reflections (1770 with F_o/σ(F_o) > 4). The final observed R factor is 0.053. K_x(Mg_xIn_1–x)F₃ has the Magnéli‐bronze structural type, which consists in a tridimensional framework of mixed [(Mg_xIn_1–x)F₆] octahedra linked together by corners. The potassium ions are mainly located in large almost fully occupied 15‐coordinated sites and in practically empty 12‐coordinated cavities.     

K and Ba distribution in the structures of the clathrate compounds KxBa16−x(Ga,Sn)136 (x = 0.8, 4.4, and 12.9) and KxBa8−x(Ga,Sn)46 (x = 0.3)

Studies of the K–Ba–Ga–Sn system produced the clathrate compounds K_0.8(2)Ba_15.2(2)Ga_31.0(5)Sn_105.0(5) [a = 17.0178 (4) Å], K_4.3(3)Ba_11.7(3)Ga_27.4(4)Sn_108.6(4) [a = 17.0709 (6) Å] and K_12.9(2)Ba_3.1(2)Ga_19.5(4)Sn_116.5(4) [a = 17.1946 (8) Å], with the type‐II structure (cubic, space group Fdm), and K_7.7(1)Ba_0.3(1)Ga_8.3(4)Sn_37.7(4) [a = 11.9447 (4) Å], with the type‐I structure (cubic, space group Pmn). For the type‐II structures, only the smaller (Ga,Sn)₂₄ pentagonal dodecahedral cages are filled, while the (Ga,Sn)₂₈ hexakaidecahedral cages remain empty. The unit‐cell volume is directly correlated with the K:Ba ratio, since an increasing amount of monovalent K occupying the cages causes a decreasing substitution of the smaller Ga in the framework. All three formulae have an electron count that is in good agreement with the Zintl–Klemm rules. For the type‐I compound, all framework sites are occupied by a mixture of Ga and Sn atoms, with Ga showing a preference for Wyckoff site 6c. The (Ga,Sn)₂₀ pentagonal dodecahedral cages are occupied by statistically disordered K and Ba atoms, while the (Ga,Sn)₂₄ tetrakaidecahedral cages encapsulate only K atoms. Large anisotropic displacement parameters for K in the latter cages suggest an off‐centering of the guest atoms.     

Ca3Ag1+xGe3–x (x = 1/3): New Transition Metal Zintl Phase with Intergrowth Structure and Alloying with Aluminum Metal

Abstract. The ternary Zintl phase Ca₃Ag_1+xGe_3–x (x = 1/3) was synthesized by the high‐temperature solid‐state technique and its crystal structure was refined from single‐crystal diffraction data. The compound Ca₃Ag_1.32Ge_2.68(1) adopts the Sc₃NiSi₃ type structure, crystal data: space group C2/m, a = 10.813(1) Å, b = 4.5346(4) Å, c = 14.3391(7) Å, β = 110.05(1)° and V = 660.48(10) ų for Z = 4. Its structure can be interpreted as an intergrowth of fragments cut from the CaGe (CrB‐type) and the CaAg_1+xGe_1–x (TiNiSi‐type) structures, and it therefore represents an alkaline‐earth member of the structure series with the general formula R_2+nT₂X_2+n with n = 4. Unlike the rare‐earth homologues that are fully ordered phases, one seventh of the atomic sites in the unit cell of the title compound are mixed occupied (roughly 2/3Ge and 1/3Ag), and this can be explained by the Zintl concept. The alloying of this phase using aluminum metal yielded the isotypic solid solution Ca₃(Ag/Al)_1+xGe_3–x, in which the aluminum for silver substitution is strictly localized in the TiNiSi substructure, revealing the very different functionality of the two building blocks.     

Kristallstrukturen aus CaBe2Ge2‐ und CeMg2Si2‐analogen Blöcken: Die Phosphide LnPt2P2−x (Ln: La,Sm)

Crystal Structures of CaBe₂Ge₂ and CeMg₂Si₂ analogous Units: The Phosphides LnPt₂P_2?x (Ln: La, Sm) Single crystals of LaPt₂P_1.44 (a = 4.174(1), c = 19.212(5) Å) were grown by reaction of vaporous phosphorus with LaPt₂ at 1050 °C during two weeks, whereas SmPt₂P_1.50 (a = 4.131(1), c = 19.086(4) Å) was synthesized by heating mixtures of the elements at 900 and 1100 °C (60 h) and annealing at 1050 °C (300 h). Both phosphides were investigated by single crystal X‐ray methods. Their crystal structures (I4/mmm; Z = 4) consist of CaBe₂Ge₂ and CeMg₂Si₂ analogous units alternating with each other along [001]. The positions of the P1 atoms are occupied incompletely causing the deviation to the 1:2:2 stoichiometry. Another compounds LnPt₂P_2?x were studied by X‐ray powder diffraction resulting in the following lattice constants: a = 4.150(1), c = 19.132(5) Å for CePt₂P_2–x, a = 4.137(1), c = 19.085(4) Å for PrPt₂P_2?x, and a = 4.127(1), c = 19.040(2) Å for NdPt₂P_2?x.     

Binäre Lanthan‐Stannide mit Sn:La‐Verhältnissen nahe 1:1 – Synthesen,Kristallstrukturen, Chemische Bindung

Four binary lanthanum stannides close to the 1:1 ratio of Sn:La were synthesized from mixtures of the elements. The structures of the compounds have been determined by means of single‐crystal X‐ray data. The low temperature (α) form of LaSn (CrB‐type, orthorhombic, space group Cmcm, a = 476.33(6), b = 1191.1(2), c = 440.89(6) pm, Z = 4, R1 = 0.0247), crystallizes with the CrB‐type. The structure exhibits planar tin zigzag chains with a Sn–Sn bond length of 299.1 pm. In contrast to the electron precise Zintl compounds of the alkaline earth elements, additional La–Sn bonding contributions become apparent from the results of band structure calculations. In the somewhat tin‐richer region, the new compound La₃Sn₄ (orthorhombic, space group Cmcm, a = 451.45(4), b = 1190.44(9), c = 1583.8(2) pm, Z = 4, R1 = 0.0674), crystallizing with the Er₃Ge₄ structure type, exhibits Sn₃ segments of the zigzag chains of α‐LaSn together with a further Sn atom in a square planar Sn coordination with increased Sn–Sn bond lengths. In the Lanthanum‐richer region, La₁₁Sn₁₀ (tetragonal, space group I4/mmm, a = 1208.98(5), c = 1816.60(9) pm, Z = 4, R1 = 0.0325) forms the undistorted tetragonal Ho₁₁Ge₁₀ structure type. Its structure, which contains isolated Sn atoms, [Sn₂] dumbbells and planar [Sn₄] rings is related to the high temperature (β) form of LaSn. The structure of β‐LaSn (space group Cmmm, a = 1766.97(6), b = 1768.28(5), c = 1194.32(3) pm, Z = 60, R1 = 0.0453), which forms a singular structure type, can be derived from that of La₁₁Sn₁₀ by the removal of thin slabs. Due to the different stacking of the remaining layers, planar [Sn₄] chain segments and linear [Sn–Sn–Sn] anions are formed as additional structural elements. The chemical bonding (Sn–Sn covalent bonding, Sn–La contributions) is discussed on the basis of the simple Zintl concept and the results of FP‐LAPW calculations (density of states, band structure, valence electron densities and electron localization function).     

Mixed Valence Tungsten(IV,V) Compounds with Layered Structures (Part II)): Synthesis and Crystal Structures of Cu1−x[W2O2Cl6] and Cu1−x[W4O4Cl10]

The reaction of CuCl with WOCl₃ at 400 °C leads to a mixture of Cu_1?x[W₂O₂Cl₆] ( 1 ) and Cu_1?x[W₄O₄Cl₁₀] ( 2 ) in form of black lustrous needles. Both compounds crystallize in space group C2/m with a = 12.7832(5) Å, b = 3.7656(2) Å, c = 10.7362(3) Å, β = 119.169(2)° for 1 and a = 12.8367(19) Å, b = 3.7715(7) Å, c = 15.955(3) Å, β = 102.736(5)° for 2 . The structures are made up of WO₂Cl₄ octahedra. In the case of 1 two octahedra are edge‐sharing via chlorine atoms to form pairs which are linked via the trans‐positioned oxygen atoms to form infinite double strands . In the structure of 2 two of these double strands are condensed via terminal chlorine atoms to form quadruple strands . Like for all members of the M_x[W₂O₂X₆] structure family (X = Cl, Br) nonstochiometry with respect to the cations M was observed. The copper content of 1 and 2 was derived from the site occupation factors of the respective structure refinements. For several crystals examined the copper content varied between x = 0.27 and 0.17 for 1 and x = 0.04 for 2 . In both structures the oxochlorotungstate strands are negatively charged and connected to layers by the monovalent copper ions, which are tetrahedrally coordinated by the non‐bridging chlorine atoms of the strands. The structure models imply disorder of the Cu⁺ ions over closely neighboured sites.     

ThSi2 Type Ytterbium Disilicide and its Analogues YbTxSi2–x (T = Cr,Fe, Co)

YbSi₂ and the derivatives YbT_xSi_2–x (T = Cr, Fe, Co) crystallizing in the α‐ThSi₂ structure type were obtained as single crystals from reactions run in liquid indium. All silicides were investigated by single‐crystal X‐ray diffraction, I4₁/amd space group and the lattice constants are: a = 3.9868(6) Å and c = 13.541(3) Å for YbSi₂, a = 4.0123(6) Å and c = 13.542(3) Å for YbCr_0.27Si_1.73, a = 4.0142(6) Å and c = 13.830(3) Å for YbCr_0.71Si_1.29, a = 4.0080(6) Å and c = 13.751(3) Å for YbFe_0.34Si_1.66, and a = 4.0036(6) Å, c = 13.707(3) Å for YbCo_0.21Si_1.79. YbSi₂ and YbT_xSi_2–x compounds are polar intermetallics with three‐dimensional Si and M (T+Si) polyanion sub‐networks, respectively, filled with ytterbium atoms. The degree of substitution of transition metal at the silicon site is signficant and leads to changes in the average bond lengths and bond angles substantially.     

Synthesis and structural characterization of the type‐I clathrates K8AlxSn46–x and Rb8AlxSn46–x (x ≃ 6.4–9.7)

Exploratory studies in the systems A–Al–Sn (A = K and Rb) yielded the clathrates K₈Al_xSn_46–x (potassium aluminium stannide) and Rb₈Al_xSn_46–x (rubidium aluminium stannide), both with the cubic type‐I structure (space group Pmn, No. 223; a ? 12.0 Å). The Al:Sn ratio is close to the idealized A₈Al₈Sn₃₈ composition and it is shown that it can be varied slightly, in the range of ca ±1.5, depending on the experimental conditions. Both the (Sn,Al)₂₀ and the (Sn,Al)₂₄ cages in the structure are fully occupied by the guest alkali metal atoms, i.e. K or Rb. The A₈Al₈Sn₃₈ formula has a valence electron count that obeys the valence rules and represents an intrinsic semiconductor, while the experimentally determined compositions A₈Al_8±xSn_38?x suggest the synthesized materials to be nearly charge‐balanced Zintl phases, i.e. they are likely to behave as heavily doped p‐ or n‐type semiconductors.     

Die Kristallstrukturen der Cyanidofluoridoborate K[BFx(CN)4–x], x = 0–4

The crystal structure of K[BF₃(CN)] (Pbcn (Nr. 60) with a = 13.3486(15) b = 6.5239(7) c = 10.0085(11) Å, and eight formula units per unit cell) has been determined and the one of K[BF₂(CN)₂] was confirmed and improved. The different networks in the complete series of borates K[BF_x(CN)_4–x], x = 0–4 are compared and discussed.     

K13CoSn17–x (x = 0.1): A New Ternary Phase Containing ­Cobalt Centered [Sn9] Cluster Synthesized via High‐Temperature Reaction

A new ternary potassium cobalt stannide, K₁₃CoSn_17–x (x = 0.1), was obtained by reacting the mixture of the corresponding pure elements at high temperature, and structurally characterized by single‐crystal X‐ray diffraction study. K₁₃CoSn_17–x (x = 0.1) crystallizes in the orthorhombic space group Pbca (No. 61) with a = 26.2799(7) Å, b = 24.1541(6) Å, c = 29.8839(6) Å, V = 18969.3(8) ų, and Z = 16. Its structure contains isolated [CoSn₉] monocapped square antiprism and [Sn₄] tetrahedron in the ratio 1:2, forming a hierarchical variant of Laves phase MgZn₂. The structural relation between the title compound with MgZn₂ as well as other binary stannides is also discussed.     

Synthesis and Structure Analysis of Aurivillius Phases Pb1‐xBi4‐+Ti1‐xMnxO15

Synthesis Pb_1‐xBi_4+xTi_4‐xMn_xO₁₅ compounds (0 ≤ × ≤ 1) were carried out by molten salts method using eutectic mixture of Na₂SO₄/K₂SO₄ salts (1:1 molar ratio) as the flux. The samples were characterized by X‐ray powder diffraction and refined by Le Bail method using Rietica program. The refinement results revealed that the compounds with the composition 0 ≤ x ≤ 0.6 formed Aurivillius phase with the space group A2₁am while the other composition (x ≥ 0.8) showed another phase beside A2₁am. The ratio b/a of the lattices constants for all the samples are larger than 1 indicating the direction of the orthorhombic along the b axis of their cells. The lattice parameters and volume of the unit cells decrease as the Mn content increasing from x = 0 to 0.6, for x ≥ 0.8 a second phase were observed. The morphologies of Pb_1‐xBi_4+xTi_4‐xMn_xO₁₅ samples were observed by SEM and show plate‐like aggregate crystals, typical of layered compounds belonging to the Aurivillius phase.     

Opening a New Series of Calcium Boridecarbides with Heterographene Nets by Ca1–x(B,C)6 and Ca1–x(B,C)8 – Two Members of the (CaB2)Cn Compound Series

Ca_1–xB₂C₄ (x ~ 0.08) and Ca_1–xB₂C₆ (x ~ 0.04) are two compounds containing heterographene‐B,C nets which were prepared by solid state synthesis and structurally characterized by X‐ray powder diffraction data. Both compounds crystallize in the space group P6/ mmm (No. 191). The lattice constants are a = 4.55971(5) Å and c = 4.4020(1) Å for CaB₂C₄ and a = 2.58390(5) Å, c = 4.43597(8) Å for CaB₂C₆. The calcium atoms are intercalated between the heterographene (B,C) nets. The calcium atom distribution in Ca_1–xB₂C₆ is disordered, leading to diffuse scattering. A model for this disorder was developed that matches well the observed diffuse scattering observed in the electron diffraction pattern. For Ca_1–xB₂C₆ and its decomposition products magnetic and electric properties are being reported.     

Synthesis and Thermal Behaviour of Compounds in the System [Ph4P]Cl/BiCl3 and the Crystal Structures of [Ph4P]3[Bi2Cl9] · 2 CH2Cl2 and [Ph4P]2[Bi2Cl8] · 2 CH3COCH3

Six polynuclear chlorobismuthates are formed in the reaction between BiCl₃ and Ph₄PCl by variation of the molar ratio of the educts, the solvents and the crystallisation methods: [Ph₄P]₃[Bi₂Cl₉] · 2 CH₂Cl₂, [Ph₄P]₃[Bi₂Cl₉] · CH₃COCH₃, [Ph₄P]₂[Bi₂Cl₈] · 2 CH₃COCH₃, [Ph₄P]₄[Bi₄Cl₁₆] · 3 CH₃CN, [Ph₄P]₄[Bi₆Cl₂₂], and [Ph₄P]₄[Bi₈Cl₂₈]. We report the crystal structure of [Ph₄P]₃[Bi₂Cl₉] · 2 CH₂Cl₂ which crystallises with triclinic symmetry in the S. G. P1 No. 2, with the lattice parameters a = 13.080(3) Å, b = 14.369(3) Å, c = 21.397(4) Å, α = 96.83(1)°, β = 95.96(1)°, γ = 95.94(2)°, V = 3943.9(1) ų, Z = 2. The anion is formed from two face‐sharing BiCl₆‐octahedra. [Ph₄P]₂[Bi₂Cl₈] · 2 CH₃COCH₃ crystallises with monoclinic symmetry in the S. G. P2₁/n, No. 14, with the lattice parameters a = 14.045(5) Å, b = 12.921(4) Å, c = 17.098(3) Å, β = 111.10(2)°, V = 2894.8(2) ų, Z = 2. The anion is a bi‐octahedron of two square‐pyramids, joined by a common edge. The octahedral coordination is achieved with two acetone ligands. [Ph₄P]₄[Bi₄Cl₁₆] · 3 CH₃CN crystallises in the triclinic S. G., P1, No. 2, with the lattice parameters a = 14.245(9) Å, b = 17.318(6) Å, c = 24.475(8) Å, α = 104.66(3)°, β = 95.93(3)°, γ = 106.90(4)°, V = 5486(4) ų, Z = 2. Two Bi₂Cl₈ dimers in syn‐position form the cubic anion. Lattice parameters of [Ph₄P]₃[Bi₂Cl₉] · CH₃COCH₃ are also given. The solvated compounds are desolvated at approximately 100 °C. [Ph₄P]₃[Bi₂Cl₉] · 2 CH₂Cl₂ and [Ph₄P]₃[Bi₂Cl₉] · CH₃COCH₃ show the same sequence of phase transitions after desolvation. All compounds melt into a liquid in which some order is observed and transform on cooling into the glassy state.     

Die Reaktionen von M[BF4] (M = Li,K) und (C2H5)2O·BF3 mit (CH3)3SiCN. Bildung von M[BFx>(CN)4—x] (M = Li,K; x = 1, 2) und (CH3)3SiNCBFx(CN)3—x, (x = 0, 1)

The Reactions of M[BF₄] (M = Li, K) and (C₂H₅)₂O·BF₃ with (CH₃)₃SiCN. Formation of M[BF_x(CN)_4—x] (M = Li, K; x = 1, 2) and (CH₃)₃SiNCBF_x(CN)_3—x, (x = 0, 1) The reaction of M[BF₄] (M = Li, K) with (CH₃)₃SiCN leads selectively, depending on the reaction time and temperature, to the mixed cyanofluoroborates M[BF_x(CN)_4—x] (x = 1, 2; M = Li, K). By using (C₂H₅)₂O·BF₃ the synthesis yields the compounds (CH₃)₃SiNCBF_x(CN)_3—x x = 0, 1. The products are characterized by vibrational and NMR‐spectroscopy, as well as by X‐ray diffraction of single‐crystals: Li[BF₂(CN)₂]·2Me₃SiCN Cmc2₁, a = 24.0851(5), b = 12.8829(3), c = 18.9139(5) Å V = 5868.7(2) ų, Z = 12, R₁ = 4.7%; K[BF₂(CN)₂] P4₁2₁2, a = 13.1596(3), c = 38.4183(8) Å, V = 6653.1(3) ų, Z = 48, R₁ = 2.5%; K[BF(CN)₃] P1¯, a = 6.519(1), b = 7.319(1), c = 7.633(2) Å, α = 68.02(3), β = 74.70(3), γ = 89.09(3)°, V = 324.3(1) ų, Z = 2, R₁ = 3.6%; Me₃SiNCBF(CN)₂ Pbca, a = 9.1838(6), b = 13.3094(8), c = 16.840(1) Å, V = 2058.4(2) ų, Z = 8, R₁ = 4.4%