Die Kristallstruktur des Hydrazinium-monofluorids

The hydrazinium monofluoride N₂H₅F crystallizes with orthorhombic symmetry, space group P2₁2₁2₁,a=4.592 Å,b=8.217 Å,c=12.341 Å, and 8 formula units. The structure was determined by the permutation method in projection, and by the three-dimensionalPatterson function, refined by Full-Matrix-Least-Squares (R=0.056). The structure consists of N₂H₅ ⁺- and F^?-ions, bonded with hydrogen bonds N?H ... N and N?H ... F. Each N₂H₅ ⁺ ion is surrounded by four F^?-ions and two nitrogen atoms of two different N₂H₅ ⁺ ions. Each F^? ion is connected with four different N₂H₅ ⁺ ions.     

Reaction des p-phenylphospholes avec le dicyclopentadienyl-difer-tetracarbonyle,synthese et etude spectrochimique des phosphaferrocenes

In boiling benzene, 1-phenyl-3,4-dimethylphosphole (L) with [(C₅H₅)Fe(CO)₂]₂ gives mainly a classical σ-complex in which L relaces one terminal CO. In boiling xylene, however, L also gives 3,4-dimethylphosphaferrocene and 2-phenyl-3,4-dimethylphosphaferrocene resulting from a P—Ph bond cleavage followed by a C-phenylation of the phospholyl nucleus in the second case. The same reaction with 1-phenylphosphole yields phosphaferrocene itself and a mixture of 2- and 3-phenylphosphaferrocene. The phosphaferrocenes thus prepared are exclusively acetylated at the phospholyl nucleus by the CH₃CGClAlCl₃ complex in CH₂Cl₂.With the unsubstituted phosphaferrocene, the acetylation takes place at the 2 and 3 positions (ratio $\text{2}\text{3}$ ～ $\text{85}\text{15}$) ¹H, ¹³C, ¹³P NMR and mass spectral data are given. The phosphaferrocene system is characterized by a very large ¹J(P—C) coupling (～60 Hz) and a very shielded phosphorus atom.     

L'extraction des lanthanides et des actinides par les oxydes d'alkylphosphine : L'extraction del'acide nitrique par quelques dioxydes de diphosphine

The distribution of nitric acid between an aqueous phase of constant or variable ionic strength and a benzene solution of diphosphine dioxide can be explained by the following reactions H⁺_a+ NO_3^-a+ DiPO₀ ? D1PO·HNO₃₀ H⁺_a+ NO_3^-a+ DiPO·HNO₃₀ ? DiPO·2 HNO₃₀ At constant ionic strength, the stability constants K₁″ were determined for the complexes 1,1-DiPO·HNO₃ (98 ± 01 (M)^-1), 1,4-DiPO·HNO₃(44±3 (M)_-1) and 1,5-DiPO·HNO₃ (51 ± 1 (M)^-1). The constants K₁₁″ for the complexes 1,1-DiPO·2 HNO₃ and 1,5-DiPO.2 HNO₃ are respectively 035±001 (M)^-1 and 62 ±0.05 (M)^-1 at 25°. With an aqueous phase of variable ionic strength, values of K₁'=54±7 (M)^-2 for 1,5-D1PO.HNO₃ and K_II'=65 ± 04 (M)^-2 for 1,5-DiPO·2 HN0₃ were obtained     

Comparaison des champs de force des niobates,tantalates et antimoniates de structure columbite et trirutile

A comparison is made between the force fields calculated for the M^IINb^V₂O₆ and M^IITa^V₂O₆ columbite series and the M^IITa^V₂O₆ and M^IISb^V₂O₆ trirutile series. The trirutile structure is shown to be particularly more rigid than the columbite structure. For this reason, the trirutile structure exists only for divalent cations of small size. The stability of the two structures and their relative modifications are then compared. From a comparison of the vibrational spectra of the rutile FeSbO₄ with those of the trirutile MSb₂O₆ compounds, a short-range order in the rutile structure is proposed.     

Zur Kenntnis des Natriumthioferrates(III)

The mixed valency compound Na₃Fe₂S₄, which is also formed in iron-sodium polysulfide melts, is oxidized and hydrated to NaFeS₂·H₂O (x ≈ 2) on air. It is shown by TGA that this hydrate loses the water reversibly between 80–140 °C. A crystal structure model for the water free phase NaFeS₂ is proposed (space group I 222,a=6.25 Å,b=10.83 Å,c=5.40 Å). The formation of NaFeS₂·xH₂O from Na₃Fe₂S₄ and the reversible phase transformation between NaFeS₂·xH₂O and NaFeS₂ are topotactic. Na⁺ ions in NaFeS₂·xH₂O are easily exchanged against K⁺, Rb⁺, Cs⁺, Tl⁺, Ca²⁺, Sr²⁺, and Ba²⁺. The high chemical reactivity of the sodium thioferrates is discussed and their crystal structures are compared with the other alkali metal thioferrate structures.     

Thermodynamique de la complexation des metaux de transition par les acides α-amines. I. Etude potentiometrique des systemes cuivre(II)—phenylalanine et cobalt(II)—phenylalanine

Protonation constants for phenylalanine anion (L) and formation constants for complexes ML⁺ and ML₂ (M = Cu²⁺ or Co²⁺) are reported for I = 1 M (Na)ClO₄ and I = 1 M (Na)Cl at 25°C. The results are compared with those of other workers.     

Die SiSi-Kopplangskonstante des Disilans

The INADEQUATE ²⁹Si spectra of H₂DSiSiDH₂ and HD₂SiSiD₂H are used to determine ²⁹Si²⁹Si coupling constants. J equal     

Intensités des transitions optiques de [PtCl4]2−

The oscillator strengths of the “d-d” transitions of the ion [PtCl₄]^2? were calculated. The method, based on the evaluation of the MO of the distorted ion, gives results in good accordance with the experimental data. The transition to ¹ B _1g (a _1g →b _1g ^* ), as a consequence of the participation of the orbital 6s, mixed with \(5d_{z^2 } \) in \(a_{1_g } ,a_{1_g } \) is characterized by a very low intensity in the case of thex,y polarization.     

Etude par RMN de la localisation des cations dans des phases ferroélectriques non-stoechiométriques derivées de LiTaO3

A ⁷Li NMR investigation of nonstoechiometric ferroelectric phases derived from LiTaO₃ has been performed on three solid solutions of formulation $\text{Li}{}_{\mathrm{1+x}}\text{Ta}{}_{\mathrm{<mtext>1?</mtext><mtext>x</mtext><mtext>5</mtext>}}\text{O}{}_3$, Li_1+xTa_1?xTi_xO₃, and Li_1?xTa_1?3x Ti_4xO₃. For the first one, based on the substitution of 1 Ta⁵⁺ by 5 Li⁺, the existence of Li⁺ in both octahedral and tetrahedral sites is confirmed. It is not excluded that the 5 Li⁺ form a small cluster within seven sites (one octahedral position and six tetrahedral ones) in the vicinity of the substituted Ta⁵⁺. For the second solid solution a large variation of the ⁷Li quadrupolar spectrum with composition has been detected, such behavior is related to the great decrease in T_c near the x = 0.10 composition.     

Die kristallstruktur des trimethylbleiazids,Me3PbN3

Me₃PbN₃ crystallizes as colourless needles in the space group P3₁21 (or P3₂21) with a 664.6 ± 5 pm; c 1378 ± 1 pm; V 527.2 »³; Z = 3; d_c 2.781 g cm^?3. With 122 independent reflections (7 non-observed by I < o(I)) and anisotropic temperature factors for the lead atom the structure was refined to a conventional R-value (without hydrogen atoms) R = 0.042. Planar Me₃Pb groups are linked by linear N₃ groups in a 3₁ (or 3₂) screw, rendering the lead atoms an almost perfect trigonal bipyramidal coordination sphere (PbN 258 pm; PbC 225 pm). The Me₃Pb units are ordered in a skew conformation; since the lead atoms are positioned 65 pm away from the screw axes the packing of the methyl groups is not influenced (Pb·Pb 474 pm).     

Determination calorimetrique de l'enthalpie de formation des alliages (Al,Ba) riches en aluminum

The heats of formation of some aluminium-barium alloys have been determined by drop calorimetry at high temperature. The heats of mixing of pure liquid Al and Ba to give the liquid alloy are Δ_mH(x_Ba=O.056, 1215 K)=?6.6 kJ mole^?1 and Δ_mH(x_Ba=O.333, 1215 K)=?31.0 kJ mole^-1. To measure its heat of formation, the solid compound Al₄Ba was precipitated by addition of pure barium from a liquid (Al, Ba) bath. It was found that Δ_fH(Al_0.8Ba_O.2, solid, 1215 K)=-(37.1 ? 1.5) kJ mole^?1 with reference to the pure metals in the solid state.     

Polarographie radiochimique des solutions acides de TeIV

With ¹²¹Te (T_1/2=17 days) radiochemical polarography of [Te^IV]≤10^?9M is possible with negligible surface coverage. Deposition of Te is diffusion controlled. The potential range of Te⁰ formation is limited at negative potential by its reduction to HTe^?.     

Conformation des dibenzoyl-2,4-pentanes. Relation avec les conformations locales des polyphenylvinylcétones atactique et isotactique

For the dl dibenzoyl-2,4-pentane, the difference δJ between the β methylene coupling constants and those of the α methine decreases slightly when the temperature is increased from ?25° to +160°. The conformational equilibrium tt ? g⁺g⁺ is not very mobile and exists only in CCl₄/CS₂ (90:10) solvent. In other solvents, the tt form is preponderant. The coupling constant variations are more important for the isotactic polymer than for the meso dibenzoyl-2,4-pentane model for which the observed variation is very weak (δJ = 0,7 Hz for ΔT = 220°). The g^?t and tg⁺ conformations have equal probability. These results are discussed in relation with those for the polymer.     

Fluorkomplexe des Siliciums in wäßriger Lösung

The solubility of SiO₂ in aqueous solutions of hexafluorosilicates at various acid concentrations has been measured. The results are interpreted in terms of a series of mononuclear siliconfluorine complexes (SiF₆, SiF₅, SiF₄). The equilibrium constants β _x6 ^′ (x=4 and 5) of the reactionxSiF₆+(6?x)SiO₂+4(6?x)H=6SiF _x +2(6?x)H₂O in 4M-LiClO₄ have been determined (β ₄₆ ^′ =7·10^?8, β ₅₆ ^′ =9·10^?2). The influence of the ionic medium and the likely structures of the complexes are discussed. No conclusion can be drawn as to number and kind of other ligands than F (OH, OH₂).     

Zum problem des fluoraustausches von Schwefeltetrafluorid

In the absence of hydrogen fluoride, the fluorine exchange in sulphur tetrafluoride proceeds in the liquid state, in solution and in the gaseous state at almost the same rate. Evidently, in these cases, the reaction is intramolecular. The observed values for the activation energy of this exchange are found to lie in the range 11.2 ± 1.0 kcal mole^-1 (liquid, solution) to 11.7 ± 1.5 kcal mole^-1 (gaseous SF₄).     

Derives α-carbonyles et “aromaticite” des phospholes trivalents

A two-step synthesis of 2-acetyl and 2-carbethoxy-phospholes involves the metalation of monomeric 3,4-dimethyl phosphole sulfides by t-butyl-lithium followed by reaction with ethyl acetate and ethyl carbonate. The phosphole sulfides thus obtained are reduced by PBu₃ or P(CH₂CH₂CN)₃ to the phospholes 20–24. In the 2-acetyl-phosphole series, variable electron transfer from the dienic system and from the phosphorus atom to the carbonyl group is monitored by ¹H and ³¹P NMR. The main decomposition path of 2-carboxy phosphole 25 in the mass spectrometer involves a PC intracyclic bond cleavage with loss of CO, in sharp contrast with pyrrole and thiophene derivatives 26 and 27. These facts militate against strong 2p_π–3p_π electronic delocalisation in the phosphole nucleus.     

Präparative,spektroskopische und röntgenographische studien an bis(dimethylmetall)di(μ-1-propinylen) des aluminiums,galliums und indiums

Dimethylpropynylmetal compounds of Al, Ga and In are formed in 40–60% yield by the reaction of NaCCCH₃ with (CH₃)₂M^IIIHal (M^III  Al, Ga, In; Hal  Cl, Br). The IR, Raman, ¹H and ¹³C NMR spectra of these, in solution dimeric, compounds are discussed. The indium derivative crystallizes in the orthorhombic space group Pnma with 4 formula units per unit cell. The lattice parameters are a  926.9; b  578.7 and c  1216.6 pm.     

Ein isoperiboles lösungskalorimeter zur messung von lösungsenthalpien der doppelchloride des magnesiums

For measuring solution enthalpies of the strong hygroscopic double chlorides, an isoperibol solution calorimeter was built. Samples of 2–5 g could be solved to a molar dilution 1 : 3000. The temperature difference between reaction vessel and thermostat was measured by a thermopile; the temperature of the thermostat was constant to 2 · 10^?4°C. From the molar enthalpies of solution (ΔH^L), enthalpies for the reactions nACl + MCl₂ = A_sMCl(_{s + 2}) were calculated: ΔHP^R = ? ΔH^L (double chloride) + ΔH^L(n Cl) + ΔH^L(MCL₂) These values are relatively small: about ? 50 kJ for the Cs-compounds, nearly zero for the K- and Na-compounds.     

Determination des capacites thermiques d'exces par calorimetrie de reaction directe

Accurate determinations of excess heat capacities,C _p ^E , of liquid and solid phases with respect to composition and temperature are shown to be possible by direct reaction calorimetry. The results are compared with those obtained by heat capacity measurements and departure from the additivity rule. In the case of solutions, the knowledge ofC _p ^E with respect to concentration permits a pertinent analysis of the short-range order. Some results concerning binary alloys, such as In-Te, Cu-Sb and Ag-Te, are given.     

Zur Synthese und Pyrolyse von Organoelement-benzasolderivaten des Phosphors,Arsens, Siliciums und Zinns

3-Organo-1,3-benzazaphospholes and -benzazarsoles as well as 3,3-disubstituted 1,3-benzazasiloles and -benzazastannoles are prepared from o-LiC₆H₆NC(Li)Bu^t and the relevant organoelement dichlorides. The heterocycles obtained are converted by flash vacuum pyrolysis into the aromatic 1H-1,3-benzazaphospholes and benzazarsoles, respectively.