Crystal Structure of Ammonia Monohydrate Phase II.
We have determined the crystal structure of ammonia monohydrate phase II (AMH II) employing a combination of ab initio computational structure prediction and structure solution from neutron powder diffraction data using direct space methods. Neutron powder diffraction data were collected from perdeu...
| Publicado en: | Journal of the American Chemical Society Vol. 131; no. 37; pp. 13508 - 13516 |
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| Autores principales: | , , , , |
| Formato: | Artículo |
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American Chemical Society
9/23/2009
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=44490779&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 44490779 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 9/23/2009 vid: 131 iid: 37 pid: 997 pub: American Chemical Society artinfo: ui: 44490779 10.1021/ja9052569 ppf: 13508 ppct: 8 formats: tig: atl: Crystal Structure of Ammonia Monohydrate Phase II. aug: au: Fortes, A. Dominic Suard, Emmanuelle Lemée-CaiIIeau, Marie-Hélëne Pickard, Christopher J. Needs, Richard J. affil: Centre for Planetary Sciences at UCL/Birkbeck, Gower Street, London, WC1E 6BT, United Kingdom Department of Earth Sciences, University College London, Gower Street, London, WC1E 6BT, United Kingdom Institut Laue-Langevin, BP156, 38042 Grenoble cedex 9, France Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, United Kingdom Theory of Condensed Matter Group, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 OHE, United Kingdom su: Ammonia Density functionals Hydrogen bonding Molecular structure Institut Laue-Langevin (Grenoble, France) Grenoble (France) France sug: subj: Grenoble (France) France Ammonia Density functionals Hydrogen bonding Molecular structure Institut Laue-Langevin (Grenoble, France) ab: We have determined the crystal structure of ammonia monohydrate phase II (AMH II) employing a combination of ab initio computational structure prediction and structure solution from neutron powder diffraction data using direct space methods. Neutron powder diffraction data were collected from perdeuterated AMH II using the D2B high-resolution diffractometer at the Institut Laue-Langevin. AMH II crystallizes in space-group Pbca with 16 formula units in a unit-cell of dimensions a = 18.8285(4) Å, b = 6.9415(2) Å, c= 6.8449(2) Å, and V= 894.61(3) Å [p = 1187.56(4) kg m] at 502 MPa, 180 K. The structure is characterized by sheets of tessellated pentagons formed by orientationally ordered O-DߪO, O-DߪN, and N-DߪO hydrogen-bonds; these sheets are stacked along the a-axis and connected by N-DߪO hydrogen bonds alone. With the exception of the simple body-centered-cubic high-pressure phases of ammonia monohydrate and ammonia dihydrate; this is the first complex molecular structure of any of the high-pressure stoichiometric ammonia hydrates to be determined. The powder structure solution is complemented by an ab initio structure prediction using density functional theory which gives an almost identical hydrogen bonding network. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2009 holdings: @attributes: islocal: N |
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