Filters
Results 1 - 10 of 29638
Results 1 - 10 of 29638.
Search took: 0.043 seconds
Sort by: date | relevance |
AbstractAbstract
[en] Using the CCSD/6-311++G(d,p) method calculations of LiHF2, NaHF2, and KHF2 molecules are realized. By the AIM method it is shown that hydrogen bond in LiHF2, NaHF2, and KHF2 molecules differ from ordinary one and is similar to covalent interaction
[ru]
С помощью метода CCSD/6-311++G(d,p) выполнены расчеты молекул LiHF2, NaHF2, KHF2. Методом AIM показано, что водородная связь в молекулах LiHF2, NaHF2, KHF2 отличается от обычной водородной связи и сходна с ковалентным взаимодействиемOriginal Title
Vodorodnaya svyaz' v dimerakh FH...FM (M=Li, Na, K): neehmpiricheskie raschety
Primary Subject
Source
19 refs., 3 figs., 2 tabs.
Record Type
Journal Article
Journal
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] A search of the Cambridge Structural Database (CSD, version 5.05, 1993) was performed in order to compare the geometrical features of the hydrogen bonds involving on the one hand amino groups and on the other hand carboxylates, sulfonates or monohydrogen phosponates. Phosphonates were not considered because only four entries containing amino and phosphonate moieities were located in the CSD. The hydroxylic group of monohydrogen phosphonates primarily acts as a hydrogen-bond donor. The three moieties under study show NH..O hydrogen bonds with similar geometrical features. This statistical analysis has focused on the hydrogen-bond distances and angles and on the distributions of the H atoms around the acceptor O atoms of carboxylates, sulfonates or monohydrogen phosphonates. (orig.)
Primary Subject
Record Type
Journal Article
Journal
Acta Crystallographica. Section B: Structural Science; ISSN 0108-7681;
; CODEN ASBSDK; v. 51(1); p. 103-107

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Huang, Ya Hui; Li, Zhuo Zhe; Li, An Yong, E-mail: syjzdxlzz@126.com, E-mail: aylifnsy@swu.edu.cn2017
AbstractAbstract
[en] Highlights: • The hexagonal boron cluster B64+ is a good new noble gas trapper. • The NgB bonds in the monocyclic compounds B6Ngn4+(n = 0–6) are covalent bonds and can be represented as the donor-acceptor model. • The NICS analysis shows that the hexagonal boron-noble gas compounds B6Ngn4+(n = 0–6) are typically aromatic systems. The hexagonal boron-noble gas compounds B6Ngn4+ (n = 1–6, Ng = HeRn) have been studied theoretically. The geometry, bond energies and thermodynamics properties are reported. For ArRn, the BNg bond length is close to the sum of the covalent radii of B and Ng, the BNg average bond energy is large up to 59.61–169.43 kcal/mol. There is large charge transfer from Ng to the boron ring, the Ng → boron σ-donation originating from the interaction between the valence p orbital of Ng and the LUMO of the boron ring is the predominant contribution towards the NgB bond stabilization. The NICS analysis shows that B6Ngn4+ have aromaticity.
Primary Subject
Secondary Subject
Source
S000926141730893X; Available from http://dx.doi.org/10.1016/j.cplett.2017.09.046; Copyright (c) 2017 Elsevier B.V. All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Record Type
Journal Article
Journal
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Lu, Jia-Syun; Yang, Ming-Chung; Su, Ming-Der, E-mail: midesu@mail.ncyu.edu.tw2017
AbstractAbstract
[en] Highlights: • The B3LYP, B3PW91, and M06-2X computational methods were used. • The theoretical observations demonstrate that only sterically bulky substituents can greatly stabilize the triply bonded RAlPR molecules. • These conclusions are based on both the thermodynamic and the kinetic viewpoints. The effect of substitution on the potential energy surfaces of triple-bonded RAlPR (R = F, OH, H, CH3, SiH3, SiMe(SitBu3)2, SiiPrDis2, Tbt (C6H2-2,4,6-{CH(SiMe3)2}3), and Ar∗ (C6H3-2,6-(C6H2-2,4,6-i-Pr3)2)) compounds was investigated by using the theoretical methods (i.e., M06-2X/Def2-TZVP, B3PW91/Def2-TZVP, B3LYP/LANL2DZ+dp, and CCSD(T)). The theoretical examinations reveal that all of the triple-bonded RAlPR species prefer to adopt a bent form with a roughly perpendicular bond angle (Al–P–R). In addition, the theoretical evidence demonstrates that only the bulkier substituents can efficiently stabilize the central AlP triple bond. Moreover, the theoretical analyses (the natural bond orbital, the natural resonance theory, and the charge decomposition analysis) indicate that the bonding characters of the triply bonded RAlPR molecules should be described as R′AlPR′. That is to say, the AlP triple bond contains one conventional σ bond, one conventional π bond, and one donor-acceptor π bond. Nevertheless, the theoretical conclusions based on the poor overlap populations between Al and P elements suggest the AlP triple bond in such an acetylene analogues (RAlPR) is likely to be very weak.
Primary Subject
Secondary Subject
Source
S0009261417307935; Available from http://dx.doi.org/10.1016/j.cplett.2017.08.032; Copyright (c) 2017 Elsevier B.V. All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Record Type
Journal Article
Journal
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
No abstract available
Primary Subject
Source
24 refs.
Record Type
Journal Article
Journal
Canadian Journal of Chemistry; v. 51(1); p. 70-76
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Koetzle, T.F.; Lehmann, M.S.
The hydrogen bond: recent developments in theory and experiments vol. 21976
The hydrogen bond: recent developments in theory and experiments vol. 21976
AbstractAbstract
[en] Neutron diffraction studies have led to the precise determination of H-atom positions in 18 crystalline α-amino acids. These structures are all stabilized by three-dimensional networks of H-bonds and significant differences occur among corresponding bond distances and angles for those groups involved in H-bonding. Specifically, there is a good inverse correlation between N-H and H...O distances for N-H...O bonds. (Auth.)
Primary Subject
Source
Schuster, P.; Zundel, G.; Sandorfy, C. (eds.); p. 459-469; ISBN 0720403154;
; 1976; North-Holland; Amsterdam, The Netherlands

Record Type
Book
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] Elasticity of structural complexes in sulfates, chromates, and molybdates of uranyl was investigated quantitatively using available data on U-Obr-T (Obr - bridge oxygen atom; T=S, Cr, Se, Mo) bond angles and T-O bond lengths. Only structural complexes with vertex bond between coordination polyhedrons UOn (n=6, 7) and TO4 tetrahedrons were considered. Analysis of distribution of U-Obr-T bond angle values indicated on raised elasticity of U-Obr-Mo in comparison with sulfates and chromates. This fact defined greater structural variability of uranyl molybdates and possibility of skeleton structures building up
[ru]
Проведено количественное исследование гибкости структурных комплексов в сульфатах, хроматах и молибдатах уранила на основе доступных данных по валентным углам U-Obr-T (Obr - мостиковый атом кислорода; T=S, Cr, Se, Mo) и длинам связи T-O. Рассматривались только структурные комплексы, в которых наблюдается вершинная связь между координационными полиэдрами урана UOn (n=6, 7) и тетраэдрами TO4. Анализ распределения величин валентных углов U-Obr-T указывает на повышенную гибкость связок U-Obr-Mo по сравнению с сульфатами и хроматами, что обусловливает большее структурное разнообразие молибдатов уранила и возможность построения каркасных структурOriginal Title
Sravnitel'noe izuchenie gibkosti strukturnykh kompleksov v sul'fatakh, khromatakh i molibdatakh uranila
Primary Subject
Source
53 refs.; 1 tab.; 2 figs.
Record Type
Journal Article
Journal
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Sruthi, P.K.; Sarkar, Shubhra; Ramanthan, N.; Sundararajan, K., E-mail: sundar@igcar.gov.in
Proceedings of the national conference on light matter interaction at nanoscale2019
Proceedings of the national conference on light matter interaction at nanoscale2019
AbstractAbstract
[en] Interaction of phosphoryl chloride (POCl3) with CH2Cl2 and CCl4 has been studied using matrix isolation infrared and ab initio computations. Computations performed at MP2 level of theory using aug-cc-pVDZ basis set indicated a 1:1 phosphorus bonding interaction for the POCl3-CH2Cl2 and POCl3-CCl4 and the heterodimers are generated at low temperature in N2 and Ar matrixes and characterized using infrared spectroscopy. The multifaceted interaction characteristics were further analyzed using NBO, AIM and EDA analyses. (author)
Primary Subject
Source
Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Board of Research in Nuclear Sciences, Mumbai (India); Materials Research Society of India, Bangalore (India); 167 p; ISBN 978-81-933428-3-1;
; 2019; [2 p.]; LMIN-2019: national conference on light matter interaction at nanoscale; Kalpakkam (India); 15-17 Jul 2019

Record Type
Book
Literature Type
Conference
Country of publication
Reference NumberReference Number
Related RecordRelated Record
INIS VolumeINIS Volume
INIS IssueINIS Issue
Lin, Qisheng; Miller, Gordon J.
Ames Laboratory (AMES), Ames, IA (United States). Funding organisation: USDOE Office of Science - SC, Basic Energy Sciences (BES) (SC-22) (United States)2017
Ames Laboratory (AMES), Ames, IA (United States). Funding organisation: USDOE Office of Science - SC, Basic Energy Sciences (BES) (SC-22) (United States)2017
AbstractAbstract
[en] Intermetallic compounds represent an extensive pool of candidates for energy related applications stemming from magnetic, electric, optic, caloric, and catalytic properties. The discovery of novel intermetallic compounds can enhance understanding of the chemical principles that govern structural stability and chemical bonding as well as finding new applications. Valence electron-poor polar intermetallics with valence electron concentrations (VECs) between 2.0 and 3.0 e–/atom show a plethora of unprecedented and fascinating structural motifs and bonding features. Furthermore, establishing simple structure-bonding-property relationships is especially challenging for this compound class because commonly accepted valence electron counting rules are inappropriate.
Primary Subject
Source
IS-J--9512; OSTIID--1417363; AC02-07CH11358; Available from http://www.osti.gov/pages/biblio/1417363; DOE Accepted Manuscript full text, or the publishers Best Available Version will be available free of charge after the embargo period
Record Type
Journal Article
Journal
Accounts of Chemical Research; ISSN 0001-4842;
; v. 51(1); p. 49-58

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
AbstractAbstract
[en] A survey of the geometry and environment of water molecules in crystalline hydrates is presented. Histograms and correlation analyses are based on 97 crystal structures accurately determined by neutron diffraction, and include data from 183 water molecules, each donating two hydrogen bonds. The sample is analyzed according to the nature of the hydrogen-bond acceptors and of the coordinated cations. Cases of bifurcated hydrogen bonds are also discussed. The hydrogen bonds tend to be linear and the acceptors tend to be located close to the water plane. The tendency of coordination bonds to be collinear with the direction of one of the lone pairs of the O or their bisector increases with the strength of the bonds. The length of the W-H bond, which, on average, is shorter than in the gas phase, is correlated to the strength of the donated hydrogen bond and to the nature of the acceptor as well as to the type of coordination. On average, W-H is shorter for weaker hydrogen bonds, lower electronegativity of the acceptors and a triangular (as opposed to tetrahedral) type of coordination. The H-W-H angle is, on average, about 2.50 wider than in the gas phase; this widening is correlated to the type of coordination (larger for triangular), to the strength of the hydrogen bond, and to the A...W...A angle between acceptors. Differences between the dimensions of water molecules in gas and solid phases are shown to be effective and not due to uncorrected thermal effects. (Auth.)
Record Type
Journal Article
Journal
Acta Crystallographica. Section B: Structural Crystallography and Crystal Chemistry; ISSN 0567-7408;
; v. 38(9); p. 2331-2341

Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
1 | 2 | 3 | Next |