Far-Out Order In Solvents

Solutes may affect solvent networks over longer distances than previously realized, two separate research teams report. The results will help scientists understand how solvents influence the stability and reactivity of molecules and particles, as well as how those solutes in turn affect the properties of solvents. Mirijam Zobel and Reinhard B. Neder of Friedrich-Alexander University Erlangen-Nuremberg, in Germany, along with Simon A. J. Kimber of the European Synchrotron Radiation Facility, located in Grenoble, France, looked at the effects of colloidal metal and metal oxide nanoparticles on alcohols and hexane using high-energy X-ray scattering (Science 2015, DOI: 10.1126/science.1261412). The nanoparticles were 2.5 to 7 nm in diameter. The researchers found that the nanoparticles induced order distinguishable from bulk solvent as far as 2 nm out from the nanoparticle surface. Matthew J. DiTucci, Sven Heiles, and Evan R. Williams of the University of California, Berkeley, studied gas-phase clusters of Fe(CN)₆^3– in water using infrared photodissociation spectroscopy (J. Am. Chem. Soc. 2015, DOI: 10.1021/ja5119545). They found that a single Fe(CN)₆^3– molecule orients water molecules and influences the hydrogen-bond network out to the surface of clusters involving as many as 70 water molecules. Clusters of that size have a radius of about 0.8 nm from the ion.