Zur Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 42. Trilithiumheptaphosphid Li3P7: Darstellung,Struktur und Eigenschaften

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 42. Trilithiumheptaphosphide Li₃P₇: Preparation, Structure, and Properties Trilithium heptaphosphide, Li₃P₇, has been prepared by reaction of the elements at 870 K in Nb and Ta ampoules, respectively. The bright yellow (solventfree) substance crystallizes in a new structure type (P2₁2₁2₁; a = 974.2(1) pm; b = 1053,5(1) pm; c = 759,6(1) pm; Z = 4). The structure is closely related to the plastically crystalline Rb₃P₇ type of structure (Li₃Bi variant). The heptaphosphanortricyclene anions P₇^3? are surrounded by 12 Li cations and connected one to each other in a complex manner. The anion exhibits a differentation of distances and angles typical for ionic nortricyclenes X₇^3? (P? P distances: d?(basis) = 224.9 pm; d?(basis-bridge) = 214.7 pm; d?(bridge-bridgehead) = 217.6 pm). The distances Li to P are in the range of 250 ≤ d(Li? (2b)P^?) ≤ 270 pm. The P? P and Li? P bond distances are equivalent to meaningful Pauling bond orders PBO. On heating in closed ampoules, Li₃P₇ shows an endothermic effect at 900 K, corresponding to a first order phase transition into a HT phase of unknown nature up to now. On thermal decomposition no congruent dissociative sublimation occurs in contrast to the other heptaphosphides M₃P₇, but LiP and Li₃P are formed, the latter evaporates congruently dissociative, Solutions of Li₃P₇ in en show valence fluctuation of the P₇^3? anions already at room temperature (δ ³¹P-NMR = ? 122.1). Further reactions of Li₃P₇ are reported as well as the structural differences between Li₃P₇ and the solvates Li₃P_7solv3 are discussed.     

Zur Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 44. Tricäsiumheptaphosphid Cs3P7: Darstellung,Struktur und Eigenschaften

Chemistry and Structural Chemistry of Phosphides and Ployphosphides. 44. Tricesium Heptaphosphide Cs₃P₇: Preparation, Structure, and Properties Tricesium heptaphosphide is prepared from the elements by a quantitative reaction at 1200 K in Nb ampoules. Slow cooling yield the bright yellow α-Cs₃P₇, quenching the yellow orange coloured β-Cs₃P₇. The crystalline α-Cs₃P₇ transforms at 552 K in a first order phase transition to the plastically crystalline β-Cs₃P₇. Both modifications are sensitive against moisture and oxygen and are completely soluble in ethylendiamine yielding a pale yellow solution. At room temperature the ³¹P nmr spectra of such solutions show only one singulett, which corresponds to the valence tautomerism of the P₇^3? anion. α-Cs₃P₇ crystallizes in a new structure type (P4₁, a = 904.6(1) pm; c = 1671.4(4) pm; Z = 4). The structure is formed by heptaphospha-nortricyclene anions P₇^3? and Cs⁺ cations. The cs atoms connect the anions forming a three-dimensional arrangement (d?(Cs? P) = 374 pm), not allowing the fragmentation into discrete Cs₃P₇ units. The P? P distances differ by their function in the nortricyclene anion. Each P₇ group is surrounded by 12 Cs atms. β-Cs₃P₇ crystallizes in the Li₃Bi type of structure (Fm3 M; a(573 K) = 1130.5(1)pm; Z = 4). The P atoms of the P₇^3? anions surround the Bi positions with an orienational disorder. The orientation has been investigated with a mixed crystal Ca₃(P₇)_2/3(P₁₁)_1/2 (Fm3 m; a (298 K) = 1149.5(9) pm; Z = 4).     

Zur Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 46. Tetrarubidiumhexaphosphid und Tetracäsiumhexaphosphid: Darstellung,Struktur und Eigenschaften von Rb4P6 und Cs4P6

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 46. Tetrarubidiumhexaphosphide and Tetracesiumhexaphosphide. Preparation, Structure, and Properties of Rb₄P₆ and Cs₄P₆ Tetrarubidium and tetracesiumhexaphosphide have been prepared quantitatively by reaction of the elements in sealed Nb ampoules at 870 K and 920 K, respectively. Both compounds are black semiconductors (E_G ≈︁ 1.3—1.6 eV) and show metallic lustre. Their crystal structures are orthorhombic defect variants M₄P₆□₂ of the hexagonal AlB₂ type structure. Characteristic building units are planar isometric P₆ rings with bond lengths d(P P) = 215 and 214 pm, respectively, representing an aromatic 10° system with one double bond, delocalized about six bonds. Thermal decomposition in Ta crucibles yields quantitatively M₃P₇. The compounds M₄P₆ disproportionate in ethylendiamine into M₃P₇, and M₃P, as revealed by ³¹P n.m.r. spectra. In the down field region a singulett (Δ(α-K₄P₆) = 331; Δ(Rb₄P₆) = 337; Δ(Cs₄P₆) = 348) is observed, which can be ascribed to the valence tautomeric hexaphosphene (4). The internal vibrations of the P₆ ring have been observed by i.r. and raman-spectra. For Cs₄P₆ the fundamental vibrations are v(A_1g)=356 cm⁻¹ and v(E_2g)=507 and 202 cm⁻¹, respectively, and show the same sequence as for benzen. Semiempirical LCAO-MO calculations show, that in the series P₆ⁿ⁻ with n=2,4, 6 the anion P₆²⁻ is the most stable one but the unit M₂P₆⁻¹ becomes more stable as the other isomers by forming the M₂[μ-(η⁶⁻P₆)] complex. Among the isomers of P₆⁴⁻ the hexagonal planar 10π system is about 7 eV more stable than the isomeric bicyclo-tetraanion.     

Zur Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 581) Tetrabariumtriphosphid,Ba4P3: Darstellung und Kristallstruktur

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 58. Tetrabariumtriphosphide, Ba₄P₃: Preparation and Crystal Structure Ba₄P₃ is obtained from the elements in the molar ratio 4:3 or by reaction of Ba₃P₂ and Ba₅P₄ in the molar ratio 1:1 (steel ampoules with inner corundum crucibles; 1 490 K). The greyish black, easily hydrolysing compound crystallizes in a new structure type oP56. The structure shows two crystallographically independent dumbbells P₂^4? (d(P? P) = 225 and 232 pm) and isolated ions P^3? corresponding to (Ba²⁺)₈(P₂^4?)₄(P^3?)₄. The partial structure of the Ba atoms forms a complex network of trigonal prisms with tetrahedral and square pyramidal holes, as well as polyhedra with 14 faces (CN 10) which are icosahedron derivatives. The P^3? anions center trigonal prisms and the 14 face polyhedron. The P-atoms of the P₂^4? dumbbells center neighboring trigonal prisms with common square faces. (Pbam (no. 55); a = 1 325.4(2) pm, b = 1 256.2(2) pm, c = 1 127.3 pm; Z = 8).     

Chemie und Strukturchemie von Phosphiden und Polyphosphiden. 53. Darstellung,Eigenschaften und Schwingungsspektren der Käfiganionen P113− und As113−

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 53. Preparation, Properties, and Vibrational Spectra of the Cage Anions P₁₁^3? and As₁₁^3? The Zintl-phases M₃X₁₁ (M = Na, K, Rb, Cs; X = P, As) are prepared from the elements or from M₃X₇ and X. The compounds undergo a first-order phase transition from the crystalline to the plastically crystalline state. Unit cell and space group of both modifications and the transition temperature T_c are determined. The vibrational spectra of the crystalline compounds and the Raman spectrum of the P₁₁^3? anion in en-solution as well are measured. The assignment of the frequencies is given, based on the 32-D₃ symmetry of the X₁₁^3? cage anion. Normal coordinate analysis is carried out in terms of Cartesian coordinates to avoid the problem of redundancies in using internal coordinates. The force constants [mdyn Å^?1] obtained for the characteristic bonds r, s, and t are: f = 1.34, f = 1.20, f = 1.08; f = 1.1, f = 0.91. Normal vibrations and the potential energy distribution (PED) are discussed.     

Zur Chemie und Strukturchemie der Phosphide und Polyphosphide. 20. Darstellung,Struktur und Eigenschaften der Alkalimetallmonophosphide NaP und KP

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 20. Preparation, Structure, and Properties of the Alkali Metal Monophosphides NaP and KP The monophosphides NaP and KP were prepared by reaction of the elements in sealed glass ampoules at 725 K and 765 K, respectively. NaP yields as black reflecting needles, whereas KP is formed as microcrystalline substance with colour of coke. The compounds react very rapidly with aqueous reagents forming solid polymeric yellow phosphanes (PH)_x and partially gaseous products. NaP and KP crystallize in the novel orthorhombic NaP type (P 2₁2₁2₁; a = 603,8 pm; b = 564.3 pm; c = 1 014.2 pm and a = 650.0 pm; b = 601.6 pm; c = 1 128.8 pm; Z = 8, respectively) characterized by onedimensional infinite ¹∞(P^?) helices of covalent twofold bonded P-atoms with mean bond length P? P = 223.9 pm. The compounds can be described as Zintl-phases with M⁺ and P^? with respect to the structure. The range of existence of the NaP type and the LiAs type structure can be separated by the radii ratios. The volume increment for P^? is V(P^?) = 18.0 cm³mol^?1. For the bond energy E(P? P) in the monophosphides a value of 248 kJ · mol^?1 is calculated. The structures are discussed in detail together with related compounds.     

Beiträge zur Chemie der Uranfluoride und -oxidfluoride. II. Darstellung und Schwingungsspektren von α- und β-Uranpentafluorid

On the Chemistry of Uranium Fluorides and Oxide Fluorides. II. Preparation and Vibrational Spectra of α- and β-Uranium Pentafluoride By reaction of a saturated solution of UF₆ in anhydrous HF with HBr β-UF₅ was prepared in a simple manner. β-UF₅ was changed into α-UF₅ by heating in the presence of UF₆. The IR and RAMAN spectra of the dimorphs are reported and discussed.     

Darstellung und Eigenschaften von Tm13F32 - δ

Preparation and Properties of Tm₁₃F_32-δ A new phase of composition TmF_2.38–2.42 was prepared by reduction of solid TmF₃ with gaseous Tm applying the double-cell technique. The deeply brown compound can be described by the formula Tm₁₃F_32-δ. It is isotypic with Yb₁₃F_32-δ and is structurally closely related to Na₇Zr₆F₃₁. It crystallizes in a rhombohedral superstructure (R3 ) which can be derived from the fluorite structure. Crystallographic data and lattice parameters, which were obtained from Guinier powder patterns, are communicated.     

Organische Phosphorverbindungen XXII. Darstellung und Eigenschaften von diprimären α,ω-Bis-phosphino-alkanen

The preparation and properties of diprimary α,ω-bis-phosphino-alkanes of the general structure H₂P(CH₂)_n PH₂ (n = 1, 2, 3, 4) are described. Their reactions with N-hydroxymethyl-dialkylamines and with olefins, which yield ditertiary α,ω-bisphosphino-alkanes, (R₂NCH₂)₂P(CH₂)_nP(CH₂NR₂)₂ and R₂P(CH₂)_nPR₂, respectively, are also reported. The physical properties of two new α,ω-bis-dialkylphosphinyl-alkanes have been determined.     

Darstellung und Struktur von α-CrPO4. Beiträge zum thermischen Verhalten von wasserfreien Phosphaten. I

Contributions on the Thermal Behaviour of Anhydrous Phosphates. I. Preparation and Structure of α-CrPO₄ By a chemical transport reaction (1100°C → 1000°C) using chlorine as transporting agent we obtained dark-green, well shaped crystals of α-CrPO₄. The compound crystallizes in the space group Imma. The lattice constants are a = 10.403(2), b = 12.898(2), c = 6.299(1) Å. The crystal structure has been determinated from single crystal data and refined to a conventional residual of R = 0.038 (1481 unique reflections, 34 variables). The structure consists of CrO₆-octahedra and PO₄-tetrahedra. Especially remarkable are pairs of edge sharing CrO₆-octahedra which are connected with two PO₄-tetrahedra at opposite edges. Parallel to the a- and b-axis are large channels extending through the whole structure.     

Struktur und Eigenschaften von Cd4SiS6 Zur Kenntnis von Cd4SiSe6

The structure of Cd₄SiS₆ (crystal data see ?Inhaltsübersicht”?) has been solved from single crystal X-ray data. SiS₄ and distorted CdS₄ tetrahedra (Si–S 2.101–2.132 Å, Cd–S 2.510–2.694 Å) are linked three-dimensionally by sharing corners in such a way that 2/3 of the S atoms have 2 Cd + 1 Si as bonded neighbors (pyramidal coordination), the rest is tetrahedrally cordinated by 4 Cd. The new defect tetrahedral structure, which is also representative for the isotypic series Cd₄GeS₆, Hg₄SiS₆ Hg₄GeS₆ and Cd₄GeSe₆, has a strongly distorted packing of the S atoms and shows no close relationship to known types. The Si–S bonds contain only very little π-contributions, similar to the Ge–S and Sn–S bonds in thiogermanates and -stannates. The vibrational spectra of Cd₄SiS₆ are reported and discussed. Cd₄SiSe₆, isotypic with Cd₄SiS₆, has been prepared by reaction of CdSe, Si and Se at 800–1000°.     

Darstellung,Struktur und Eigenschaften von Ag10Si3S11

Preparation, Crystal Structure and Properties of Ag₁₀Si₃S₁₁ The novel orange-red thiosilicate Ag₁₀Si₃S₁₁ is formed besides Ag₈SiS₆ by the high - temperature reaction between Ag₂S, Si and S. The single crystal structure analysis shows the compound to be silver orthothiosilicate thiodisilicate-(1:1) Ag₁₀(SiS₄)(Si₂S₇). The mean Si? S bond lengths are 2.137 Å for SiS₄^(4?) and 2.129 Å for the hitherto unknown Si₂S₇^(6?). The cation sublattice is slightly imperfect. inferring a certain mobility of the Ag⁺ ions. Ag₁₀Si₃S₁₁ crystallizes in the triclinic space group P1 . Lattice constants see ?Inhaltsübersicht”?. The vibrational spectrum (IR) shows absorptions within the characteristic spectral regions for asymmetric and symmetric stretching vibrations of the SiS₄ tetrahedra at 490–515 and 423–433 cm^?1.     

Die Kristallstrukturen von α- und β-K3OCl

The Crystal Structures of α- and β-K₃OCl The orange coloured compound K₃OCl has been prepared. It exists in a low temperature modification (α-K₃OCl) and a high temperature modification (β-K₃OCl). The transition temperature is 364 ± 5 K. The crystal structures were determined by x-ray diffraction. α-K₃OCl crystallizes at room temperature in the orthorhombic space group Pbnm (Z = 4) with the cell parameters a = b = 723.9(2) pm and c = 1 027.7(2) pm in the anti-GdFeO₃-structure type. The high temperature modification β-K₃OCl crystallizes (Z = 1) in the cubic space group Pm3m in the β-Ag₃SI-structure type with a = 516.2(2) pm (T = 393 K).     

TiOBr; Darstellung,Eigenschaften und Struktur*

TiOBr was prepared by reaction of Ti with TiO₂ and Br₂. The compound forms fiat reddish-brown needles and shows a temperature independent weak paramagnetism. It crystallises in the orthorhombic system (Pmmn; a = 3.787, b = 3.487, c = 8.529 Å) with the FeOCl type of structure. The interatomic distances are Ti?O = 1.952; 2.245 Å (2X) and Ti?Br = 2.544 Å (2X).     

Zur Darstellung und Struktur von LaTa3O9 Röntgenographische und elektronenmikroskopische Untersuchungen

Preparation and Structure of LaTa₃O₉. X-Ray and Electronmicroscopic Investigations In the system La₂O₃/Ta₂O₅ a new ternary compound LaTa₃O₉ could be prepared by chemical transport in a temperature gradient T₂ → T₁ (1100 → 1040°C; Cl₂ was added). LaTa₃O₉ is orthorhombic, space group Pnma–D with the lattice constants a = 6.59₅, b = 7.66₄, and c = 12.48₁ Å. In the structure ribbons of pentagonal TaO₇-bipyramids are recognizable parallel to the a-direction. These ribbons are connected with each other in the (010) plane by TaO₆-octahedra. The tunnels formed in this way are occupied by La atoms. High resolution transmission electron microscopy images of the structure were made along the [010] direction. They were interpreted by using images calculated on the basis of the multi-slice method.     

Zur Darstellung und Struktur von tetragonalem und rhombischem (Al,Be)B12 vom Typ des β-AlB12

Preparation and Structure of Tetragonal and Orthorhombic (Al, Be)B₁₂ of the β-AlB₁₂ Type Details are given about the preparation and structural characterisation of tetragonal AlBeB₂₄ which may also be named tetragonal β-(Al, Be)B₁₂ due to its relation to β-AlB₁₂. Now an orthorhombic form of the β-(Al, Be)B₁₂ has been obtained which is considered as an intermediate between tetragonal β-(Al, Be)B₁₂ and β-AlB₁₂. It has the same unit cell as the A-phase of β-AlB₁₂. The formation of tetragonal or orthorhombic β-(Al, Be)B₁₂ depends on a statistic or an ordered dislocation of aluminium atoms from the 2a-positions of the basic tetragonal lattice. The degree of ordering may be regarded in connection with a partial substitution of aluminium resp. beryllium atoms on or near icosahedral boron places.     

Darstellung,Struktur und magnetische Eigenschaften der Natriumeisenchalkogenide Na6FeS4 und Na6FeSe4

Synthesis, Structure, and Magnetic Properties of the Sodium Iron Chalcogenides Na₆FeS₄ and Na₆FeSe₄ The compounds Na₆FeS₄ and Na₆FeSe₄ have been synthesized by fusion reactions of sodium carbonate with iron and chalcogen in a stream of hydrogen. Structural investigations on single crystals show that both compounds crystallize in an atomic arrangement isotypic with Na₆ZnO₄ (space group P6₃mc). The structure is characterized by isolated [FeX₄]-tetrahedra. The magnetic susceptibilities show Curie-Weiss behaviour. The deviations at low temperatures are obviously caused by antiferromagnetic interactions.     

Verbesserte Darstellung,Kristallzüchtung und Strukturanalyse von P4O6S2 und P4O6S3

Improved Syntheses, Crystal Growth, and Crystal Structure Determination of P₄O₆S₂ and P₄O₆S₃ Syntheses and single crystal growths of the title compounds are described. Both compounds crystallize in the space group P2₁/c (P₄O₆S₂: a = 11.293(4); b = 6.457(3); c = 11.588(4) Å; β = 90.29(2)°, 2 450 diffractometer data, R_w = 0.035/P₄O₆S₃: a = 15.611(5); b = 8,303(3); c = 9.697(4) Å; β = 127.12(2)°, 2 481 diffractometer data, R_w = 0.034). The structural data for the series P₄O₆S_n (n = 1 – 4) thus completed are compared to their oxide analogues P₄O₆O_n (n = 1 – 4). The changes in the geometry of the P₄O₆-cage in course of its successive oxidation are discussed.