Calculation of the Geometry of the Water Molecule in Liquid Water

1997 ◽  
Vol 101 (51) ◽  
pp. 10039-10044 ◽  
Author(s):  
Thomas M. Nymand ◽  
Per-Olof Åstrand
Keyword(s):  
Water Molecule ◽  
Liquid Water

Is seven the minimum number of water molecules per ion pair for assured biological activity in ionic liquid–water mixtures?

2015 ◽  
Vol 17 (22) ◽  
pp. 14454-14460 ◽  
Author(s):  
Hiroyuki Ohno ◽  
Kyoko Fujita ◽  
Yuki Kohno
Keyword(s):  
Phase Transition ◽  
Ionic Liquid ◽  
Biological Activity ◽  
Water Molecule ◽  
Liquid Water ◽  
Ion Pair ◽  
Water Molecules ◽  
Minimum Number ◽  
Transition Behaviour

The biological activity and phase transition behaviour of IL–water mixtures, called hydrated ILs, were found to change non-linearly at a water molecule to ion pair ratio of around 7 : 1.

scholarly journals LIQUID WATER MOLECULE IONIZATION BY FAST ELECTRON IMPACT

Anales AFA ◽  
2010 ◽  
Vol 22 (1) ◽  
pp. 120-123
Author(s):  
M.L. de Sanctis ◽  
O. Fojón ◽  
C. Stia ◽  
R. Vuilleumier ◽  
M.F. Politis
Keyword(s):  
Water Molecule ◽  
Electron Impact ◽  
Liquid Water ◽  
Fast Electron

The structure of the water molecule in liquid water

1981 ◽  
Vol 42 (4) ◽  
pp. 757-765 ◽  
Author(s):  
J.G. Powles
Keyword(s):  
Water Molecule ◽  
Liquid Water

A theoretical treatment of cation exchangers - III. The hydration of cations in polystyrene sulphonates

1955 ◽  
Vol 228 (1174) ◽  
pp. 322-341 ◽  
Keyword(s):  
Water Molecule ◽  
Water Activity ◽  
Adsorption Isotherms ◽  
Liquid Water ◽  
Adsorbed Water ◽  
Isopiestic Method ◽  
Water Molecules ◽  
Hydration Water ◽  
Monovalent Cations ◽  
Free Energies

The adsorption of water by the polystyrene sulphonates of cations has been investigated at 0 and 25° C, using an isopiestic method. The adsorption isotherm and the heats (enthalpies) and entropies of hydration have been obtained for the monovalent cations H, Li, Na, K, Cs, NH4, Ag and for the divalent cations Be, Mg, Ca, Sr, Ba, Hg. With the exception of H, which gives a smooth enthalpy-water-content curve, all monovalent cations show a more or less marked step in the differential enthalpy of adsorbed water between the first and second water molecule adsorbed per ion, thereafter the steps are less clearly defined. The differential entropies show similarities to those calculated for a B. E. T. isotherm, except that the curves show two minima which correspond to approximately 0.15 and 1.5 molecules of water/ion. The adsorption isotherms follow more or less the model of the B. E. T. isotherm, with several significant differences: ( a ) the volatility of the second and further water molecule/ion is not that of liquid water, but only tends to reach this value after several molecules/ion are adsorbed, and the energy levels of the first successive water molecules, though rising rapidly, differ substantially from that of liquid water; ( b ) the adsorption process of the first water molecule is significantly different from a Langmuir mechanism, and varies approximately as the one-half power of the water activity. The knowledge of the free energies, enthalpies and entropies permits a fair analysis of the hydration mechanism into its individual steps, which then permits a calculation of the standard state enthalpies and entropies of the first hydration steps. Both functions show a markedly linear relationship with the ionic radius of the unhydrated ion when summed up for the first two water molecules adsorbed. The knowledge of the adsorption isotherms permits one to differentiate between water adsorbed with zero free energy (swelling water) and the excess adsorbed water (cationic and anionic hydration water). The amount of hydration water associated with the cations has been obtained in this way both for mono- and divalent ions. The amount varies both with the water activity and with temperature. It is clear from the small free energies of hydration of all monovalent ions that the association of almost all water molecules is very loose, and is not related to the co-ordination number of the ions.

A continuous mixture of two different dimers in liquid water

2014 ◽  
Vol 16 (44) ◽  
pp. 24479-24483 ◽  
Author(s):  
L. C. Pardo ◽  
A. Henao ◽  
S. Busch ◽  
E. Guàrdia ◽  
J. Ll. Tamarit
Keyword(s):  
Water Molecule ◽  
Liquid Water ◽  
Relative Water ◽  
Continuous Mixture

Liquid water is formed by a continuous mixture of two different dimers (cis and trans) with distinct energies related to different relative water molecule orientations.

Oxygen-18 isotope effects in the liquid water–pyridine system as a probe of intermolecular forces

1977 ◽  
Vol 55 (16) ◽  
pp. 2966-2970 ◽  
Author(s):  
Robert H. Betts ◽  
Jan Bron ◽  
Wayne D. Buchannon ◽  
Kwok-Ying D. Wu
Keyword(s):  
Carbon Dioxide ◽  
Water Molecule ◽  
Mole Fraction ◽  
Liquid Water ◽  
Vapour Pressure ◽  
Isotope Effects ◽  
Pure Water ◽  
Intermolecular Forces ◽  
Average Water ◽  
Gaseous Carbon Dioxide

Oxygen-18 exchange between gaseous carbon dioxide and water in liquid water–pyridine mixtures is used as a probe for changes in intermolecular forces when the composition of the system is changed from pure water to pure pyridine. In agreement with results obtained previously by other methods, it is found that the interaction energy of an 'average' water molecule with the medium decreases when the mole fraction of pyridine is varied from zero to unity. The experimental results are related to the vapour pressure isotope effect, P(H218O)/P(H216O), of the binary mixtures. The utility of the Stern – Van Hook – Wolfsberg equation for vapour pressure isotope effects has been investigated. In addition, a plot of the equilibrium constant of the oxygen-18 exchange reaction vs. the mole fraction of pyridine presents no evidence of the formation of stoichiometric pyridine–water complexes.

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