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1.
The heat capacity due to the hindered rotation of the ammonium ion has been computed for (NH4)2SiF6 and (NH4)2SnCl6 and compared to that derived from the observed heat capacity. The torsional frequencies for (NH4)2SiF6 and (NH4)2SnCl6 are 226 cm?1 and 190 cm?1 respectively, and the barriers to rotation are 3210 calories/mole and 1470 calories/mole, respectively.  相似文献   

2.
The ammonium ion stabilizes a betaine zwitterion in the gas phase forming a salt-bridge structure, [(CH3)3N+CH2COONH4+] that is 3.7 kcal/mol less stable than the ion/molecule complex between protonated betaine and neutral ammonia, (CH3)3N+CH2COOH/NH3. DFT calculations have reversed the previously determined relative stability based on PM3 calculations and are in agreement with black-body infrared radiative dissociation experiments. A double-well potential energy surface is formed with a rather low central barrier separating the two complexes. This is conducive to efficient hydrogen/deuterium exchange in agreement with experiment. It prevents the existence of the salt-bridge complex as a distinct species under thermal conditions.  相似文献   

3.
In ground mixtures of In2O3 and NH4Y, incorporation of In+ cations into the zeolitic phase occurs upon thermal treatment by partial reductive solid-state ion exchange associated with oxidation of ammonium ions or released ammonia to N2 and NH2OH. Cationic InO+ species, created in zeolites by reductive solid-state ion exchange of In2O3/NH4-zeolite mixtures in hydrogen atmosphere and subsequent oxidation of the In+ lattice cations by oxygen, do not undergo autoreduction up to 970 K. Reductive solid-state ion exchange easily proceeds in carbon monoxide atmosphere at temperatures between 620 and 770 K. The significance of these observations for the use of indium-containing zeolites as catalysts is discussed.  相似文献   

4.
近年来,水溶性聚磷酸铵在液体肥料和复合肥料的领域受到了广泛的关注,并在发达国家中得到了大面积的推广及应用。在pH值为5.5~8.0、温度为278.15 K~323.15 K的条件下,本文采用滴定法研究Ca2+-Mg2+-Zn2+体系在聚磷酸铵溶液中的螯合规律。实验结果表明:相同质量分数的聚磷酸铵溶液对金属离子的螯合量会随着体系中Ca2+、Mg2+、Zn2+的摩尔浓度的变化而变化;随着温度的升高而逐渐降低;随着pH的增加而逐渐增加;随着聚合度的升高而逐渐增加。采用傅里叶红外光谱对聚磷酸铵和A1B3C3体系的螯合物进行表征。  相似文献   

5.
Methylpalladium(II) dithiolate complexes of the type [PdMe(SS)(ER3] (SS = S2 CNR2 (R = Me or Et), S2COEt, S2P(OR)2 (R = Et, nPr, iPr), S2PPh2; ER3 = PMePh2, PPh3, AsPh3) have been synthesized by the reaction of [Pd2Me2(μ-Cl)2(PMePh2)2] with sodium/potassium/ammonium salts of the dithio acid or by treatment of [PdMeCl(cod)] with ER3 followed by sodium/potassium/ammonium salts of the dithio ligand. All the complexes were characterized by elemental analysis, IR and nuclear magnetic resonance (1H, 31P) data.  相似文献   

6.
The non-metal NH4+ carrier has attracted tremendous interests for aqueous energy storage owing to its light molar mass and fast diffusion in aqueous electrolytes. Previous study inferred that NH4+ ion storage in layered VOPO4⋅2 H2O is impossible due to the removal of NH4+ from NH4VOPO4 leads to a phase change inevitably. Herein, we update this cognition and demonstrated highly reversible intercalation/de-intercalation behavior of NH4+ in layered VOPO4⋅2 H2O host. Satisfactory specific capacity of 154.6 mAh g−1 at 0.1 A g−1 and very stable discharge potential plateau at 0.4 V based on reference electrode was achieved in VOPO4⋅2 H2O. A rocking-chair ammonium-ion full cell with the VOPO4⋅2 H2O//2.0 M NH4OTf//PTCDI configuration exhibited a specific capacity of 55 mAh g−1, an average operating voltage of about 1.0 V and excellent long-term cycling stability over 500 cycles with a coulombic efficiency of ≈99 %. Theoretical DFT calculations suggest a unique crystal water substitution process by ammonium ion during the intercalation process. Our results provide new insight into the intercalation/de-intercalation of NH4+ ions in layered hydrated phosphates through crystal water enhancement effect.  相似文献   

7.
Ferrocenylmethyldimethylamine, FcCH2NMe2, reacts with CH2Cl2 in either the presence or absence of non-coordinating counterions to give equimolar amounts of the bis(ferrocenylmethyl)dimethyl ammonium salts (FcCH2)2NMe2+X (X=PF6, SbF6, BPh4 or Cl, 1ad) and the corresponding protonated ammonium salts FcCH2NMe2H+ which have been isolated as the SbF6 and Cl salts 2b,d. The reaction proceeds via fragmentation of an intermediate quaternary chloromethylated ammonium ion to chloromethylferrocene, FcCH2Cl, and dimethyliminium chloride NMe2CH2+Cl. The parent amine acts as a nucleophile toward FcCH2Cl to give 1ad and as a base toward NMe2CH2+ to give FcCH2NMe2H+, NMe2H and (Me2N)2CH2. The FcCH2Cl intermediate is intercepted by NEt3 while KCN or LiH do not successfully compete with FcCH2NMe2. A new, non-toxic, selective, high-yield route to 1d is also presented. Electrochemistry and UV–vis spectroelectrochemistry reveal, that the two identical redox centers in 1ad are essentially non-interacting. Individual E1/2 values have been determined for different solvents by digital simulation. The corresponding ferrocenium salts were prepared by either chemical or electrochemical means and accordingly characterized. Our studies are augmented by X-ray structure analyses of 1b, 1d and 2d. 1d contains three different cation conformers and four molecules of water per unit cell. The latter are hydrogen bonded to the chloride counterions to form one-dimensional infinite chains parallel to the a axis.  相似文献   

8.
Ab initio Molecular orbital calculations with large basis sets and incorporating correlation are used to examine the structures and relative energies of the vinyloxonium (CH2CHOH2+) and 1-hydroxyethyl (CH3CHOH+) cations. The best structure of the vinyloxonium ion has the OH2 plane perpendicular to the CCO plane. The energy difference between the vinyloxonium and 1-hydroxyethyl cations is predicted to be 92 kJ mol?1, substantially greater than a recent experimental estimate of 41 ± 12 kJ mol?1  相似文献   

9.
Supersonic jet expansions of mixtures of nitric oxide with either nitrous oxide or carbon dioxide have been investigated over a wide range of relative concentrations. Mixed molecular cluster ions of the form (NO) m + (N2O)n and (NO) m + (CO2)n are detected following non-resonant two-photon ionization. Over a wide range of intermediate concentrations, the cluster ion distributions (NO) 3 + (N2O)n and (NO) 3 + (CO2)n with n30 are significantly more intense than clusters containing other numbers of nitric oxide molecules. The extra abundance of these species is attributed to their especially stable structures and several possible forms are discussed. An intriguing possibility involves a stable cyclic nitric oxide trimer (or ion) when combined with nitrous oxide or carbon dioxide clusters.  相似文献   

10.
The hindered rotational energy levels of the ammonium ion in (NH4)2SnCl6 have been computed. These energy levels are used to interpret the librational frequencies, tunneling frequencies, and rotational heat capacity of the ammonium ion.  相似文献   

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