PerspectiveChemistry

Ion Chemistry Mediated by Water Networks

+ See all authors and affiliations

Science  15 Jan 2010:
Vol. 327, Issue 5963, pp. 280-281
DOI: 10.1126/science.1184555

You are currently viewing the summary.

View Full Text

Summary

The remarkable properties of liquid water derive largely from its ability to form fluctuating networks of hydrogen bonds. However, even in the gas phase, where clusters of only a few water molecules may form, their sparse hydrogen-bonded networks may still absorb energy and stabilize reactants and products (13), stabilize intermediates as catalysts (1), or act as reaction partners. In the D region of the ionosphere (70 to 85 km above Earth), the positively charged ions that form there, such as NO+, can formally transfer charge to one water molecule and add an OH group to form a neutral species (such as HONO). The resulting protonated water networks (47) are regarded as the major positive-charge carrier in the D region, which is the lowest ionospheric layer that affects radio communications. On page 308 of this issue, Relph et al. (8) report on a combined experimental and theoretical study that tries to unravel the relation between the hydrogen-bonding arrangement of a set of water molecules around an NO+ ion and the chemical activity of this ensemble. Their results bear on a key open question: Are there particular water clusters that account for most of the reactivity?