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. 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).     

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. 36. Tetrakaliumhexaphosphid: Darstellung,Struktur und Eigenschaften von α-K4P6 und β-K4P6

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 36. Tetrapotassiumhexaphosphide: Preparation, Structure, and Properties of α-K₄P₆ and β-K₄P₆ Tetrapotassiumhexaphosphide has been prepared quantitatively by reaction of the elements at 870 K in sealed Nb and Ta ampoules, respectively. Two crystalline modifications are formed: α-K₄P₆ is stable below 850 K, β-K₄P₆ is stable above this temperature. Both compounds are black semiconductors (E_G(α) = 0.55 eV) with metallic lustre. The orthorhombic structures are defect variants of the hexagonal AlB₂ type structures (K₄P₆□₂) and of a different stacking sequence of this type. Characteristic building units are planar isometric P₆ rings, formed by a specific ordering of defects in the partial structure of the major component. The short P? P distances (215.5 pm and 215.0 pm, respectively) are about 30 pm shorter than the distances compared with a single bond (221 pm). They represent one double bond which is delocalized about six bonds or an aromatic 2π-system. The thermal decomposition in tantalum crucibles, the reaction with quartz walls as well as the reaction with benzophenone in monoglyme yields quantitatively K₃P₇. The reaction with RCl ? Me₃SnCl in monoglyme at 223 K results in the formation of P₇R₃ with high yield (75%). Very probably the valence fluctuating hexaphosphene(4) system is formed at 195 K in the primary reaction step (³¹P-NMR, singulett at 473 ppm downfield).     

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.     

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.     

Darstellung,Struktur und Eigenschaften von Kupfer(II)-Carbonat

Synthesis, Structure, and Properties of Cupric Carbonate CuCO₃ can be prepared from azurite, malachite or CuO by reaction with CO₂ using a pressure of 20 kb at a temperature of 500°C. The compound is monoclinic, its spacegroup is Pa? C (Nr. 7); the lattice constants are: a = 6.092, b = 4.493, c = 7.030 Å, β = 101.34°. From the structure determination follows the coordination number 5 with a distorted square pyramid of oxygen around the metal. The IR sepctrum ist explained on the basis of site-symmetry considerations.     

Darstellung und Struktur von Li5Ga4

Preparation and Crystal Structure of Li₅Ga₄ Li₅Ga₄ has been established as further, hitherto unknown phase in the LiGa system. The new compound crystallizes in the trigonal system (P3 m1—D_3d³) with a = 437.5 ± 0.2 pm, c = 825.7 ± 0.2 pm, c/a = 1.885. The structure is strongly related to those of LiGa and Li₃Ga₂.     

Zur Darstellung und Struktur neuer Modifikationen von CeTa3O9

Preparation and Structure of New CeTa₃O₉ Modifications The modifications M? , O? and P? CeTa₃O₉ could be prepared by chemical transport reactions (T₂ → T₁; T₂ = 1100°C; T₁ = 1000°C) with chlorine as transport agent. M? CeTa₃O₉ crystallizes in the monoclinic space group C 2/m with a = 12.415(1) Å, b = 7.6317(8) Å, c = 6.5976(8) Å, β = 93.31(1)°; Z = 4; R = 4.88%, R_w = 3.67%. The structure consists of two types of Ta? O-polyhedra. Especially remarkable are chains of edge sharing pentagonal TaO₇-bipyramids which are connected by TaO₆-octahedra at opposite sides. Tunnels running along [010] are created by the framework of Ta? O-polyhedra and are filled with Ce in levels of y = 1/2 and y = 0. O? CeTa₃O₉ crystallizes orthorhombically with a = 6.5429(7) Å, b = 7.6491(7) Å, c = 12.583(1) Å and is isostructural to O? LaTa₃O₉ (space group: Pnma). O? CeTa₃O₉ contains the same characteristic structural units namely pentagonal TaO₇-bipyramides and TaO₆-octahedra. The difference between O? and M? CeTa₃O₉ is based on the orientation of the tunnels: in the orthorhombic modification they are arranged zigzag-like, in the latter parallel. Both modifications of CeTa₃O₉ can be irreversibly converted into the well-known perovskite-related P? CeTa₃O₉ structure with a lower density by heating in air to 1200°C.     

Struktur und Eigenschaften von CuxMoO3

Structure and Properties of Cu_xMoO₃ Cu_0.185MoO₃ was found in the coexistence range MoO₃? Cu₄Mo₅O₁₇? MoO₂. The structure was determined by X-ray diffraction on selected monocrystals. The compound crystallizes in the monoclinic space group C2/c (a = 1 668.8(3), b = 932.2(3), c = 543.1(2) pm, β = 102,78(1)°, Z = 2).     

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 LaNb5O14

Preparation and Structure of LaNb₅O₁₄ Single crystals of LaNb₅O₁₄ could be prepared by chemical transport reactions (T₂ → T₁; T₂ = 1050°C; T₁ = 950°C) using chlorine as transport agent. LaNb₅O₁₄ crystallizes in the orthorhombic space group Pbem with cell dimensions a = 3.8749(2) Å; b = 12.4407(6) Å and c = 20.2051(9) Å; Z = 4; R = 6.28%, R_w = 3.74%. The structure consists of two types of Nb? O-polyhedra. Especially remarkable are chains of edge-sharing pentagonal NbO₇-bipyramids, which are interconnected by corner-sharing NbO₆-octahedra. Tunnels running in a-direction are created by this framework of NbO₆- and NbO₇-polyhedra. Lanthanum atoms are located in these tunnels at levels inbetween the niobium atoms. The relationship to O? LaTa₃O₉ and M? CeTa₃O₉ type structures will be discussed.     

Zur Chemie und Strukturchemie der Phosphide und Polyphosphide. 26. Dibariumheptaphosphidchlorid Ba2P7Cl,eine Verbindung mit dem polycyclischen Anion P

Chemistry and Structural Chemistry of Phosphides and Polyphosphides. 26. Dibariumheptaphosphidechloride Ba₂P₇Cl, a Compound with the Polycyclic Anion P Ba₂P₇Cl is formed by the synthesis of Ba₃P₁₄ from the elements in a melt of BaCl₂ (dehydrated) at 1170 K. The compound forms light rubyred platelets which decompose in protic systems immediately to phosphanes. Ba₂P₇Cl crystallizes in the space group P2₁/m with Z = 2 formular units (a = 1172.6(2) pm; b = 682.9(1) pm; c = 633.7(1) pm; β = 95.27(2)°). The structure (964 reflexions hkl, R = 0.035) is related to the NaCl type, in which the half of the anionic positions is occupied by the gravi-centers of the polycyclic anions P. The bond lengths d(P? P) show the typical topological dependence for the anionic heptaphosphanortricyclene system: (d : 226.4 pm in the three-membered ring; 214.5 pm ring to bridge; 217.2 pm bridge to bridge head). The Ba atoms are surrounded by 9 and 10 non metallic atoms, respectively. Cl^? is coordinated tetrahedrally by Ba.     

Zur Kenntnis der Chemie und der Struktur von Olefin-monocyano-dicarbonyl-ferrat-Anionen

About Chemistry and Structure of Olefin-monocyano-dicarbonyl-ferrate Anions By the reactions of olenFe(CO)₃ [olen = C₅H₈(isoprene), C₇H₁₀(cycloheptadiene-1,3), C₈H₁₄(2,5-dimethylhexadiene-1,3)] with sodium bis [trimethylsilyl]amide the new anions [olenFe(CO)₂CN]^? are formed. All so far known [olenFe(CO)₂CN]^? complexes [olen = C₅H₈(isoprene), C₇H₁₀[cycloheptadiene-1,3], C₄H₆(butadiene), C₅H₈(pentadiene-1,3), C₆H₈(cyclohexadine-1,3), C₆H₁₀(2,3-dimethylbutadiene), C₈H₈(cyclooctatetraene)] have fluctional structures in solution as shown by ¹³C NMR spectroscopic investigations. At low temperatures only the isomer exists, in which the CN^? ligand and one of the two CO molecules occuppy the basal positions of a square pyramide together with 2 C atoms of the diene part.     

Zur Darstellung und Struktur von LaTa7O19 Röntgenographische und elektronenmikroskopische Untersuchungen

Preparation and Structure of LaTa₇O₁₉. X-Ray and Electronmicroscopic Investigations In the system La₂O₃/Ta₂O₅ a new ternary compound LaTa₇O₁₉ could be prepared by chemical transport in a temperature gradient T₂ → T₁ (1120 → 1020°C; Cl₂ was added). LaTa₇O₁₉ is hexagonal, space group P6 with the lattice constants a = 6.23₆ and c = 19.99₅ Å. In the structure double layers of pentagonal TaO₇-bipyramids are recognizable perpendicular to [001]-direction. They alternate with a single layer consisting of La? O and Ta? O coordination polyhedra. Images of the structure were made with high resolution transmission electron microscopy along the [001]-direction. Despite the length of the axis the computer simulation based on the multi-slice method agreed well with the experimental images.     

Li2PtH2, Darstellung und Struktur

Li₂PtH₂, Synthesis and Structure The synthesis of Li₂PtH₂ succeeded in decomposing Li₅Pt₂H₉ at 220°C in an argon atmosphere. X-ray investigations on a powdered sample and elastic neutron diffraction experiments on the deuterated compound led to the complete structure. Li₂PtH₂ crystallizes in the space group Immm with Z = 2. The structure is characterized by [PtH₂]^2? -dumb-bells which are hitherto unknown in platinum compounds. The arrangement of the [PtH₂]^2? -anions and of the lithium cations shows a close relationship to the hydride Li₂PdH₂ which crystallizes tetragonal I-centred.