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51.
Low-Temperature Synthesis of Oxyhalides, YOX (X = Cl, Br, I), as the Source of Impurity in the Preparation of Trihalides, YX3, via the Ammonium Halide Route. Analogy of YOCl and YSCl Ammonium halides, NH4X (X = Cl, Br, I), react with Y2O3 and Y2S3, respectively, at temperatures as low as 230=C (X = Cl), 280=C (Br), and 360=C (I) (molar ratio 12:1) to yield (NH4)3YX6, NH3, and H2O (H2S). The choice of smaller ratios than 12:1 (for example 2:1) results in the formation of oxyhalides, YOX, via the reaction of (NH4)3YX6 with surplus Y2O3. This reaction is therefore the actual source of impurity of rare-earth trihalides in their preparation via the ammonium halide routes. 相似文献
52.
Ternary Rare-Earth Halides of the A2MX5 Type (A = K, In, NH4, Rb, Cs; X = Cl, Br, I) Ternary rare-earth (=M) chlorides, bromides, and iodides In2MCl5, (NH4)2MCl5, Rb2MCl5, Cs2MCl5, CsRbMCl5, K2MBr5, Rb2MBr5, K2MI5, and Rb2MI5 have been synthesized. Single crystals of In2PrCl5, Rb2PrCl5, K2PrBr5, and K2PrI5 were grown and the structures refined. The other halides were characterized by x-ray powder patterns. They are isotypic either with K2PrCl5(orthorhombic, Pnma, Z = 4, hexagonal arrangement of chains of edge-connected polyhedra [PrX7]) or with Cs2DyCl5 (orthorhombic, Pbnm, Z = 4, hexagonal arrangement of cis-corner-connected octahedra [DyCl6]) which may be discriminated in structure field diagrams. The thermal expansion was investigated für Cs2LuCl5 and Rb2PrX5 (X = Cl, Br, I). 相似文献
53.
Jan Cocquyt Ulf Olsson Gerd Olofsson Paul Van der Meeren 《Colloid and polymer science》2005,283(12):1376-1381
Two endothermic transitions, at 36°C and 44°C, were observed with differential scanning calorimetry (DSC) upon heating dioctadecyldimethylammonium
bromide vesicle dispersions that were equilibrated below 15°C while in samples kept at 25°C there was only the transition
at 44°C, which was shown to be the gel to liquid–crystalline transition by 1H-NMR measurements. The transition at 36°C was reversed in an exothermic transition around 13°C upon cooling. The slowness
of this transition at ambient temperatures suggests that the presence of the transition at 36°C in a DSC upscan depends strongly
on the sample history. 相似文献
54.
Trimethylsilyl Derivatives of Vb Elements. VII. Crystal Structures of Lithium Bis(trimethylsilyl)bismuthide · DME and of Tetrakis(trimethylsilyl)dibismuthane as well as Some Comments on the Crystal Structure of Bis(4-methoxyphenyl)ditellane Colourless lithium bis(trimethylsilyl)bismuthide · DME 1 1,2-Dimethoxyethan (DME); Tetrahydrofuran (THF) 1 and green, metallic lustrous tetrakis(trimethylsilyl)dibismuthane 2 crystallize isotopic to their antimony homologues [1, 2]. As it is shown by crystal structure determinations { 1 : ?90°C; I 4 2d; a = 1017,3(4); c = 3738,0(26) pm; Z = 8; R w = 0,065; 2 : + 20°C; P2 1 /c; a = 680,9(4); b = 1704,8(13); c = 1197,9 (10) pm; β = 119,46(6)°; Z = 2; R w = 0,084} both compounds form chains which in the case of bismuthide 1 are built up as screws of alternating bismuth and lithium atoms; bonding further to two trimethylsilyl groups or to the chelating DME ligand both atoms gain coordination number 4 {Li? Bi 292(3); Bi? Si 263.3(14) pm; Bi? Li? Bi 132(1); Li? Bi? Li 148(1); φ(Li? Bi? Li? Bi) 83°}. In the case of dibismuthane 2 the centrosymmetric molecules are strung, their Bi-Bi groups forming nearly linear zigzag chains with shortened intermolecular contact distances {Bi-Bi 303.5(3); Bi …? Bi 380.4(3); Bi? Si 268 pm; Bi? Bi …? Bi 169; Bi? Bi? Si 97.4(5) and 92.0(5)°}. Structure and properties of 2 are compared with those of similar compounds; the crystal structure of brown, green metallic lustrous bis(4-methoxyphenyl)ditellane 5 already published by Ludlow and McCarthy[3] is reinvestigated with respect to very short intermolecular Te…?Te contacts. 相似文献
55.
Gerd Meyer 《无机化学与普通化学杂志》1981,478(7):39-51
Indium Sesquichloride, In2Cl3: a Pseudobinary, Mixed-valence Indium(I) Hexachloroindate(III) Colorless In2Cl3, obtained by reduction of InCl3 with metallic In, according to In[InIIICl6] a pseudobinary, mixed-valence indium(I) hexachloroindate(III), crystallizes orthorhombic (Pnma, Z = 32) with a = 1261.4(3), b = 2523.8(5), c = 1456.2(2) pm (Guinier-Simon data), Vm(In2Cl3) = 87.3 cm3 × mol?1. InIII occupies octahedral holes separated from each other (d?(InIII? Cl) = 251 pm). Coordination numbers of 7 to 11 are observed for InI (d?(InI? Cl) = 329–359 pm). In2Cl3 is isotypic with α-Tl2Cl3. 相似文献
56.
(C2H10N2)[BPO4F2] — Strukturbeziehungen zwischen [BPO4F2]2— und [Si2O6]4— Colourless crystals of (C2H10N2)[BPO4F2] were prepared from mixture of ethylendiamine, H3BO3, BF3 · C2H5NH2, H3PO4 and HCl under mild hydrothermal conditions (220 °C). The crystal structure was determined by single crystal methods (triclinic, P1¯ (no. 2), a = 451.85(5) pm, b = 710.20(8) pm, c = 1210.2(2) pm, α = 86.08(1)°, β = 88.52(2)°, γ = 71.74(1)°, Z = 2) and contains infinite tetrahedral zweier‐single‐chains {[BPO4F2]2—} which are isoelectronic (48e—) with the polyanions {[Si2O6]4—} of the pyroxene family. 相似文献
57.
Mohamed El-Sayed Hardy Müller Gerd Rheinwald Heinrich Lang Stefan Spange 《Monatshefte für Chemie / Chemical Monthly》2003,50(11):361-370
N-(2′-Hydroxy-4′-N,N-dimethylaminobenzylidene)-4-nitroaniline [HDBN] has been used as a model for investigating intra- and intermolecular D–A (donor–acceptor) interactions in various environments
by means of UV/Vis spectroscopy. UV/Vis spectra of HDBN have been measured in various solvents, ethanolic solutions of different pH, adsorbed on silica, and in the solid state. A bathochromic shift of νmax is observed with increasing the dipolarity/polarizability and HBD (hydrogen bond donor) capacity of the solvent, which is
described by means of a multiple LSE (linear solvation energy) relationship in terms of the empirical Kamlet-Taft solvent polarity parameters. The adsorption of HDBN on Aerosil? 300-silica particles in non-HBA (hydrogen bond acceptor) solvents is explained in the same sense. Mobile protons and sol–gel
entrapping cause a hypsochromic shift due to protonation of the lone electron pair of the 4′-N,N-dimethylamino group. Hydroxide ions attack the 2′-hydroxy group which causes a bathochromic shift. A strong intramolecular
hydrogen bond between the 2′-hydroxyl hydrogen and the imine nitrogen atom is present in the solid-state structure causing
an unprecedented bathochromic shift. 相似文献
58.
Ternary Halides of the A3MX6 Type. II. The System Ag3?xNaxYCl6: Synthesis, Structures, Ionic Conductivity . The influence of the substitution of Ag+ by Na+ ions on the crystal structure and the ionic conductivity of Ag3YCl6 (stuffed LiSbF6-type structure) has been investigated. The system Ag3?xNaxYCl6 forms a complete solid solution. The stuffed LiSbF6-type structure is stable for all compositions. For compounds with Na+ contents of x > 1.67, the cryolite-type structure is observed as the high-temperature form. The transition temperature decreases steadily with increasing Na+ content. The “end member” phase Na3YCl6 transforms at 243 K from the monoclinic cryolite-type structure to the stuffed LiSbF6-type structure (trigonal, R3 ; a = 697.3(1), c = 1 868.4(14) pm, Z = 3; R = 0.094; Rw = 0.069). The crystal structures of Ag1.3Na1.7YCl6 (trigonal, R3 ; a = 691.5(2), c = 1 853.7(6) pm, Z = 3; R = 0.099, Rw = 0.081) and AgNa2YCl6 (trigonal, R3 ; a = 691.7(1), c = 1 853.9(5) pm, Z = 3; R = 0.099, Rw = 0.064) have also been determined. Both chlorides crystallize like Ag3YCl6 and Na3YCl6-I in the stuffed LiSbF6-type structure. The monovalent cations, Ag+ and Na+, are distributed over the five octahedral voids that are occupied by the Ag+ ions alone in Ag3YCl6. The ionic conductivity for compounds within the solid solution Ag3?xNaxYCl6 decreases with increasing Na+ content. The values for Na3YCl6 (σ = 1 · 10?6 Ω?1 cm?1 at T = 500 K) are by 2.5 to 3.5 orders of magnitude smaller than those for Ag3YCl6 (σ = 6 · 10?4 Ω?1 cm?1 at T = 500 K). 相似文献
59.
Zusammenfassung Eine Apparatur zur Bestimmung kleiner Dichtedifferenzen wird beschrieben, die einen mit einem kleinen Magneten versehenen
Schwimmer enth?lt, der durch ein in me?barer Weise ver?nderliches magnetisches Feld in der Flüssigkeit zum Schweben gebracht
wird. Zur Messung werden nur 10 ml L?sungsmittel und 10 ml L?sung ben?tigt. Die Empfindlichkeit betr?gt etwa 2 · 10−6 g/cm3 (2 Stellen der sechsten Dezimale der Dichte).
Die zum Vergleich bestimmten partiellen spezifischen Volumen von Rinder-Serumalbumin und Chymotrypsinogen ergaben für das
erstere im Konzentrationsbereich zwischen 0,04 und 0,65% einen Mittelwert von 0,7335 (20,0° C) und für das letztere einen Wert von 0,720 (21,6° C). 相似文献
60.
From a range of preparative methods, three geometric isomers of bis(diphenylarsino)methane‐dichloroplatinum(II) have been isolated, viz. cis‐PtCl2(dpam), trans, trans‐Pt2Cl4(dpam)2 and cis, trans‐Pt2Cl4(dpam)2. Their structures were determined by single‐crystal X‐ray diffraction. 相似文献