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1.
用DFT B3LYP方法及6-311G(d,p),6-311+G(d,p)和LanL2dz基组,对C6F5X+(X=Cl,Br,I,CH3)阳离子做了理论研究,优化了它们的电子基态的构型,计算了对应分子的垂直电离势(VIP)和绝热电离势(AIP).结果表明四种离子的构型的对称点群和对应分子相同,但构型参数有明显差别.B...  相似文献   

2.
The compound, (NH4)[VO(O2)2(NH3)], thermally decomposes to ammonium metavanadate, which then decomposes to vanadium pentoxide. Using a heating rate of 5 deg·min–1, the first decomposition step occurs between 74° and 102°C. The transformation degree dependence of the activation energy (-E) is shown to follow a decreasing convex form, indicating that the first decomposition step is a complex reaction with a change in the limiting stage of the reaction. Infrared spectra indicated that the decomposition proceeds via the gradual reduction of the ratio of the (NH4)2O to V2O5 units from the original 11 ratio in ammonium metavanadate, which may be written as (NH4)2O·V2O5, to V2O5.The assistance of Professor A. M. Heyns (University of Pretoria) and Professor K. L. Range (University of Regensburg) is gratefully acknowledged as well as the financial assistance of the University of Pretoria and the FRD.  相似文献   

3.
The crystal structure of Cr2H2(As2O7)(As4O12) has been determined by X-ray methods using single crystal diffractometer data (1,152 reflections,R=0.054, orthorhombic,Pmmn,a=1317.7 (7),b=1124.9 (6),c=494.3 (4) pm,Z=2). The crystal structure contains both diarsenate(V) and the hitherto unknown cyclo-tetraarsenate(V)-anions. The magnetic susceptibility follows theCurie-Weiss law (=3.86±0.01 B/Cr3+, =–31 K).
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4.
This study gives our analysis for the frequency shifts of the v2 (1708 cm-1) Raman mode in NH4Cl close to its tricritical (P=1.6 kbar) and second order (P=2.8 kbar) phase transitions. From our analysis, we extract the values of the critical exponent which describes the critical behavior of the Raman frequency shifts for this internal mode for the pressure conditions studied in NH4Cl. Our exponent value of alpha approximately 0.2 for the tricritical phase transition is close to the values of 1/16 (TTc) for the specific heat, predicted from a 3D Ising model. Our exponent values for the second order phase transition (P=2.8 kbar) for TTc are comparable with those reported in earlier studies.  相似文献   

5.
Summary The atomic arrangements within the structures of NH4Ag2(AsS2)3 [a=9.557(2),b=7.414(2),c=16.29(1) Å; =91.30(5)°; space group P21/n;R(F)=0.042] and (NH4)5Ag16(AsS4)7 [a=64.49(6),b=6.471(2),c=12.806(4) Å; =95.47(5)°; space group Cc;R(F)=0.073] were determined from single crystal X-ray data. In these two compounds the coordination spheres of the Ag atoms are quite different. In NH4Ag2(AsS2)3, the Ag atoms exhibit a [2+2]- and a [3+1]-coordination to S atoms up to 3.3 Å and with Ag atom neighbours at 2.93 Å and 3.05 Å respectively. In (NH4)5Ag16(AsS4)7, the Ag atoms are — with one exception- [4] coordinated (Ag-S<3.3 Å) and the distances to further Ag atom neighbours are greater than 3.1 Å. NH4Ag2(AsS2)3 represents an ordered cyclo-thioarsenate(III) with three-membered As3S6 rings, (NH4)5Ag16(AsS4)7 a neso-thioarsenate(V) with two split Ag atom positions. Both compounds were synthesized under moderate hydrothermal conditions.
Synthesen und Kristallstrukturen von NH4Ag2(AsS2)3 und (NH4)5Ag16(AsS4)7 mit einer Diskussion über (NH4)Sx Polyeder
Zusammenfassung Die Atomanordnungen in den Strukturen von NH4Ag2(AsS2)3 [a=9.557(2),b=7.414(2),c=16.29(1) Å; =91.30(5)°; Raumgruppe P21/n;R(F)=0.042] und (NH4)5Ag16(AsS4)7 [a=64.49(6),b=6.471(2),c=12.806(4) Å; =95.47(5)°; Raumgruppe Cc;R(F)=0.073] wurden anhand von röntgenographischen Einkristalldaten bestimmt. In diesen beiden Verbindungen sind die Koordinationsverhältnisse um die Ag-Atome sehr unterschiedlich. In NH4Ag2(AsS2)3 besitzen die Ag-Atome bis 3.3 Å eine [2+2]- und [3+1]-Koordination durch S-Atome mit weiteren Ag-Atomen bei 2.93 Å und 3.05 Å. In (NH4)5Ag16(AsS4)7 sind die Ag-Atome mit einer Ausnahme [4]-koordiniert (Ag-S < 3.3 Å), und die Abstände zu weiteren Ag-Atomen sind größer als 3.1 Å. NH4Ag2(AsS2)3 stellt ein geordnetes Cyclothioarsenat(III) mit dreigliedrigen As3S6-Ringen dar, (NH4)5Ag16(AsS4)7 ein Nesothioarsenat (V) mit zwei aufgespaltenen Ag-Positionen. Beide Verbindungen wurden unter mäßigen Hydrothermalbedingungen synthetisiert.
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6.
Reaction of 2-(phenylazo)pyridine (pap) with [Ru(PPh3)3X2] (X = Cl, Br) in dichloromethane solution affords [Ru(PPh3)2(pap)X2]. These diamagnetic complexes exhibit a weakdd transition and two intense MLCT transitions in the visible region. In dichloromethane solution they display a one-electron reduction of pap near − 0.90 V vs SCE and a reversible ruthenium(II)-ruthenium(III) oxidation near 0.70 V vs SCE. The [RuIII(PPh3)2(pap)Cl2]+ complex cation, generated by coulometric oxidation of [Ru(PPh3)2(pap)Cl2], shows two intense LMCT transitions in the visible region. It oxidizes N,N-dimethylaniline and [RuII(bpy)2Cl2] (bpy = 2,2′-bipyridine) to produce N,N,N′,N′-tetramethylbenzidine and [RuIII(bpy)2Cl2]+ respectively. Reaction of [Ru(PPh3)2(pap)X2] with Ag+ in ethanol produces [Ru(PPh3)2(pap)(EtOH)2]2+ which upon further reaction with L (L = pap, bpy, acetylacetonate ion(acac) and oxalate ion (ox2−)) gives complexes of type [Ru(PPh3)2(pap)(L)]n+ (n = 0, 1, 2). All these diamagnetic complexes show a weakdd transition and several intense MLCT transitions in the visible region. The ruthenium(II)-ruthenium(III) oxidation potential decreases in the order (of L): pap > bpy > acac > ox2−. Reductions of the coordinated pap and bpy are also observed.  相似文献   

7.
Using the thermal decomposition of [Co(NH3)6]2(C2O4)3·4H2O as a basis, the paper presents results which show how computed values of kinetic parameters are influenced by experimental conditions (ambient atmosphere, sample mass, linear heating rate) when using the non-isothermal methods and the Coats-Redfern (CR) modified equation. It also illustrates the influence of the experimental methods i.e. non-isothermal and isothermal (conventional) methods and also a quasiisothermal-isobaric one which can be recognised as equivalent to Constant Rate Thermal Analysis (CRTA). The results obtained have confirmed the significant influence of the experimental parameters as well as that of the experimental method used on the estimated values of kinetic parameters. The correlation between activation energy (E) and sample mass (m) or heating rate (β) is generally of a linear nature:E=a+bx  相似文献   

8.
The synthetic compound Pb6Cu(AsO3)2Cl7 crystallizes in space group R witha 0=9.8614(4),c 0=17.089(2)Å,Z=3. The crystal structure, determined by single crystal X-ray work, is a typical layer structure. Complex Pb6(AsO3)2Cl6 layers are combined via monovalent Cu and Cl atoms. A novel element within the structure is a [Cl3Cu(I)-As(III)O3] group with the interatomic distances (Å): Cu-Cl=2.44 (3×), As-O=1.76 (3×), Cu-As=2.34 (1×).
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9.
Viscosities for aqueous NH4Cl and tracer diffusion coefficients for22Na+,36Cl, HTO, and CH3OH, acetone and dimethylformamide (all14C-labelled) in NH4Cl supporting electrolyte are reported for 25°, together with tracer diffusion coefficients for22Na+,36Cl, and14CH3OH in 1M KI, and for14CH3OH in 1M MgCl2. The diffusion coefficient of HTO in NH4Cl solutions is slightly larger, for most of the concentration range investigated (0.05 to 4.5 M), than the value for pure water and is almost unaffected by the supporting electrolyte up to about 4M. Similar behavior is shown by CH3OH, acetone and dimethylformamide in NH4Cl solutions. Onsager limiting law behavior is approached by Cl at NH4Cl concentrations in the 0.05–0.1M region but at much lower concentrations by Na+.  相似文献   

10.
11.
The ternary uranium(III) halides A2UX5 (A = K, Rb; X = Cl, Br, I) have been prepared from the binary components AX and UX3 in sealed tantalum containers. According to their Guinier X-ray powder patterns, they all crystallize with the K2PrCl5/Y2HfS5 type of structure. Lattice constants for ambient temperature are reported. Single-crystal structure refinemens were undertaken for K2UI5 and Rb2UCl5. Magnetic susceptibility data were recorded with a SQUID magnetometer from liquid helium to room temperature. One-dimensional (intrachain) and three-dimensional antiferromagnetic ordering occur at low temperatures dependent upon the U3+? U3+ distance. Absorption spectra were recorded between 4 000 and 28 000 cm?1. They show f—f transitions typical for U3+ and, depending on the halide, very strong f—d transitions above 14 000 to 15 000 cm?1, respectively.  相似文献   

12.
Summary The crystal structure of synthetic Cu3SeO4(OH)4 was determined by single crystal X-ray methods:a=8.382 (2) Å,b=6.087 (1) Å,c=12.285 (2) Å,V=626.8 Å3,Z=4, space group Pnma,R=0.026,R w =0.021 for 1255 independent reflections (sin / 0.8 Å–1). The crystal structure is isotypic to that of the mineral antlerite, Cu3SO4(OH)4. The copper atoms are Jahn-Teller distorted with Cu[4+2]O6 polyhedra forming triple chains along [010]. These chains are linked via SeO4 tetrahedra and weak hydrogen bonds to a framework structure.
Die Kristallstruktur von synthetischem Cu3SeO4(OH)4
Zusammenfassung Die Kristallstruktur von synthetischem Cu3SeO4(OH)4 wurde mittels Einkristall-Röntgenmethoden ermittelt:a=8.382 (2) Å,b=6.087 (1) Å,c=12.285 (2) Å,V=626.8 Å3,Z=4, Raumgruppe Pnma,R=0.026,R w =0.021 für 1255 unabhängige Reflexe (sin / 0.8 Å–1). Die Kristallstruktur ist isotyp mit der des Minerals Antlerit, Cu3SO4(OH)4. Die Kupferatome sind Jahn-Teller-verzerrt, die Cu[4+2]O6 Polyeder bilden Dreierketten entlang [010]. Diese Ketten sind über SeO4-Tetraeder und schwache Wasserstoffbrücken zu einer Gerüststruktur verbunden.
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13.
Two new Pb(II) coordination polymers, [Pb(3-pdip)(L1)]?·?0.5H2O (1) and [Pb(4-pdip)(L2)] (2) [L1?=?heptane diacid, L2?=?hexane diacid, 3-pdip?=?2?-(3-pyridyl)imidazo[4,5-f]1,10-phenanthroline, 4-pdip?=?2?-(4-pyridyl)imidazo[4,5-f]1,10-phenanthroline], have been obtained from hydrothermal reactions of Pb(II) nitrate with two flexible fatty carboxylic acids and two phenanthroline derivatives. Single-crystal X-ray diffraction analysis reveals that 1 is a 1-D staircase-like double chain coordination polymer extended by binuclear [Pb2N4O8] subunits and pairs of L1 ligands. Compound 2 exhibits a 2-D (4,4) network based on bi-metallic [Pb2N6O8] units and (L2)2/(4-pdip)2 double linkers. Furthermore, adjacent chains of 1 and layers of 2 are extended into 3-D supramolecular networks by π–π stacking interactions between aromatic rings of phenanthroline groups. The organic carboxylic acids with different lengths show great influence on the shapes of Pb(II)-carboxylate double chains. Phenanthroline derivatives possessing different sites of N-donors (3-pyridyl and 4-pyridyl) determine the final coordination frameworks of 1 and 2. Photoluminescence and thermal stabilities of 1 and 2 were also investigated.  相似文献   

14.
The complete Raman spectrum of arsenolite, cubic crystalline As4O6, is reported for the first time. The previously unseen Eg mode has been found at 443 cm−1. Further, there is additional support for the assignment of the 415 cm−1 mode as T2g.  相似文献   

15.
The crystal structure of the new phase Cu7(OH)6(TeO3)2(SO4)2 [a=7.389 (1),b=7.638 (1),c=7.662 (2) Å, =75.17 (1), =75.90 (1), =84.19 (1)°;Z=1] was determined by direct methods andFourier summations from X-ray intensities, and was refined in space group P -C i 1 toR=0.039. As usual, the Cu(II) atoms are coordinated to four O atoms forming approximately a square with average Cu-O=1.96 (3) Å; one or two more distant O neighbours complete the coordination. The shape of the TeO3 group is a rather clear-cut trigonal pyramid. A disorder was found for the SO4 tetrahedra. The compound was synthesized under hydrothermal conditions [500 (10) K, saturation vapour pressure].
Herrn Prof. Dr.K. Komarek zum 60. Geburtstag gewidmet.  相似文献   

16.
On an Oxide Chloride of CoIII: Sr8Co6O15Cl4 Sr8Co6O15Cl4 was prepared for the first time by flux reaction. It crystallizes with tetragonal symmetry: space group D4h17–I4/mmm; a = 3.927; c = 31.429 Å; Z = 1. Co3+ has different coordinations. One point position show CoO6 octahedra, the other one has a CoO5Cl surrounding. An oxygen deficit exhibit partly distorted square pyramids. Sr8Co6O15Cl4 is strongly related to Ba8In6O17.5 or can be seen as Sr4Co3O7.5Cl2 as a variety of the Sr4Ti3O10 type.  相似文献   

17.
We have studied the thermal behaviour under atmospheric pressure of isotypic tetrahydrate cyclotriphosphates MII(NH4)4(P3O9)2x4H2O (M II=Cu, Ni and Co), between 25 and 1400°C, by X-ray diffraction, thermal analyses (TG and DTA) and infrared spectrometry. This study shows that the series of the compounds MII(NH4)4(P3O9)2x4H2O (M II=Cu, Ni and Co) after elimination of water, in two different stages, and ammonia leads, at 400°C to cyclotetraphosphate M2 IIP4O12 crystallized and to a thermal residue with a formula H4P4O12 which undergoes under a thermal degradation by evolving water and pentoxide phosphorus. The kinetic characteristics of the dehydration and elimination of ammonia have been determinated. The vibrational spectra of Cu(NH4)4(P3O9)2x4H2O were examined and interpreted, in the domain of the valency frequencies, on the basis of the crystalline structure of its isotypic compound Co(NH4)4(P3O9)2x4H2O whose cycle has the site symmetry C1, of our results of the calculation of the IR frequencies and the successive isotopic substitutions of the equivalent atoms (3P, 3Oi and 6Oe belonging to the P3Oi3Oe6 ring) of the P3O9 3− cycle with high symmetry D3h. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

18.
The three copper(II)-arsenates were synthesized under hydrothermal conditions; their crystal structures were determined by single-crystal X-ray diffraction methods:Cu3(AsO4)2-III:a=5.046(2) Å,b=5.417(2) Å,c=6.354(2) Å, =70.61(2)°, =86.52(2)°, =68.43(2)°,Z=1, space group ,R=0.035 for 1674 reflections with sin / 0.90 Å–1.Na4Cu(AsO4)2:a=4.882(2) Å,b=5.870(2) Å,c=6.958(3) Å, =98.51(2)°, =90.76(2)°, =105.97(2)°,Z=1, space group ,R=0.028 for 2157 reflections with sin / 0.90 Å–1.KCu4(AsO4)3:a=12.234(5) Å,b=12.438(5) Å,c=7.307(3) Å, =118.17(2)°,Z=4, space group C2/c,R=0.029 for 1896 reflections with sin / 0.80 Å–1.Within these three compounds the Cu atoms are square planar [4], tetragonal pyramidal [4+1], and tetragonal bipyramidal [4+2] coordinated by O atoms; an exception is the Cu(2)[4+1] atom in Cu3(AsO4)2-III: the coordination polyhedron is a representative for the transition from a tetragonal pyramid towards a trigonal bipyramid. In KCu4(AsO4)3 the Cu(1)[4]O4 square and the As(1)O4 tetrahedron share a common O—O edge of 2.428(5) Å, resulting in distortions of both the CuO4 square and the AsO4 tetrahedron. The two Na atoms in Na4Cu(AsO4)2 are [6] coordinated, the K atom in KCu4(AsO4)3 is [8] coordinated by O atoms.Die drei Kupfer(II)-Arsenate wurden unter Hydrothermalbedingungen gezüchtet und ihre Kristallstrukturen mittels Einkristall-Röntgenbeugungsmethoden ermittelt:Cu3(AsO4)2-III:a = 5.046(2) Å,b = 5.417(2) Å,c = 6.354(2) Å, = 70.61 (2)°, = 86.52(2)°, = 68.43(2)°,Z = 1, Raumgruppe ,R = 0.035 für 1674 Reflexe mit sin / 0.90 Å–1.Na4Cu(AsO4)2:a = 4.882(2) Å,b = 5.870(2) Å,c = 6.958(3) Å, = 98.51(2)°, = 90.76(2)°, = 105.97(2)°,Z = 1, Raumgruppe ,R = 0.028 für 2157 Reflexe mit sin / 0.90 Å–1.KCu4(AsO4)3:a = 12.234(5) Å,b = 12.438(5) Å,c = 7.307(3) Å, = 118.17(2)°,Z = 4, Raumgruppe C2/c,R = 0.029 für 1896 Reflexe mit sin / 0.80 Å–1.Die Cu-Atome in diesen drei Verbindungen sind durch O-Atome quadratisch planar [4], tetragonal pyramidal [4 + 1] und tetragonal dipyramidal [4 + 2]-koordiniert; eine Ausnahme ist das Cu(2)[4 + 1]-Atom in Cu3(AsO4)2-III: Das Koordinationspolyeder stellt einen Vertreter des Übergangs von einer tetragonalen Pyramide zu einer trigonalen Dipyramide dar. In KCu4(AsO4)3 haben das Cu(1)[4]O4-Quadrat und das As(1)O4-Tetraeder eine gemeinsame O—O-Kante von 2.428(5) Å, was eine Verzerrung der beiden Koordinationsfiguren CuO4-Quadrat und AsO4-Tetraeder bedingt. Die zwei Na-Atome in Na4Cu(AsO4)3 sind durch O-Atome [6]-koordiniert, das K-Atom in KCu4(AsO4)3 ist [8]-koordiniert.
Zur Kristallchemie dreier Kupfer (II)-Arsenate: Cu3(AsO4)2-III, Na4Cu(AsO4)2 und KCu4(AsO4)3
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19.
Summary Crystals of monoclinic Fe2(SeO4)3 were synthesized under hydrothermal conditions. The structure was determined by single crystal X-ray methods and refined in space group P21/n with 2 646 independent reflections (sin /<0.7 Å–1) toR=0.033,R w=0.037:a=8.530 (2) Å,b=8.888 (2) Å,c=11.952 (2) Å, =91.13 (1)°,V=906.0 Å3,Z=4. The crystal structure is isotypic with the monoclinic modification of Fe2(SO4)3, containing two different Fe(III) and three Se(VI) atomic positions. The FeO6 and SeO4 polyhedra are only slightly distorted, the mean Fe-O bond lengths are 1.986 Å and 2.004 Å, the average distances within the SeO4 tetrahedra are each 1.628 Å. The isolated FeO6 octahedra only share corners with SeO4 tetrahedra to build a framework structure.
Synthese und Kristallstruktur von monoklinem Fe2(SeO4)3
Zusammenfassung Kristalle von monoklinem Fe2(SeO4)3 wurden unter Hydrothermalbedingungen gezüchtet. Die Struktur wurde mit Einkristall-Röntgenmethoden bestimmt und in der Raumgruppe P21/n mit 2 646 unabhängigen Reflexen (sin /<0.7Å–1) aufR=0.033,R w=0.037 verfeinert:a=8.530(2) Å,b=8.888(2) Å,c=11.952(2) Å, =91.13(1)°,V=906.0 Å3,Z=4. Die Kristallstruktur ist isotyp mit der monoklinen Modifikation von Fe2(SO4)3, sie enthält zwei unterschiedliche Fe(III) und drei Se(VI) Atompositionen. Die FeO6-Polyeder sind nur gering verzerrt, die mittleren Fe-O Bindungslängen sind 1.986 Å und 2.004 Å, die mittleren Abstände in den SeO4-Tetraedern sind jeweils 1.628 Å. Die isolierten FeO6-Oktaeder sind nur über gemeinsame Ecken mit SeO4-Tetraedern verbunden, wobei eine Gerüststruktur entsteht.
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20.
The refinement of the crystal structure of Cu2O(SO4), dolerophanite, [a=9.370 (1) Å,b=6.319 (1) Å,c=7.639 (1) Å, =122.34 (1)°; space group C 2/m;Z=4;R=0.035] confirmed the trigonal dipyramidal coordination of one Cu(II) atom (mean distance Cu-O=2.025 Å). One O atom is tetrahedrally surrounded by four Cu(II) atoms; the mean Cu(II)-O distance of 1.918 Å compares well to [O Cu(II)4] tetrahedra found in inorganic crystal structures.de|Die Verfeinerung der Kristallstruktur von Cu2O(SO4), Dolerophanit, [a=9.370 (1) Å,b=6.319 (1) Å,c=7.639 (1) Å, =122.34 (1)°; Raumgruppe C 2/m;Z=4;R=0.035] bestätigte die trigonal dipyramidale Koordination des einen Cu(II)-Atoms (mittlerer Cu-O-Abstand=2.025 Å). Ein O-Atom ist tetraedrisch von vier Cu(II)-Atomen umgeben; der mittlere Cu(II)-O-Abstand von 1.918 Å entspricht den in ähnlichen [O Cu(II)4]-Tetraedern von anorganischen Kristallstrukturen gefundenen Werten.
Cu2O(SO4), Dolerophanit: Verfeinerung der Kristallstruktur mit einem Vergleich von [O Cu(II)4]-Tetraedern in anorganischen Verbindungen
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