title: A Non-Exploding Alkali Metal Drop on Water: From Blue Solvated Electrons to Bursting Molten Hydroxide.
abstract: Alkali metals in water are always at the brink of explosion. Herein, we show that this vigorous reaction can be kept in a non-exploding regime, revealing a fascinating richness of hitherto unexplored chemical processes. A combination of high-speed camera imaging and visible/near-infrared/infrared spectroscopy allowed us to catch and characterize the system at each stage of the reaction. After gently placing a drop of a sodium/potassium alloy on water under an inert atmosphere, the production of solvated electrons became so strong that their characteristic blue color could be observed with the naked eye. The exoergic reaction leading to the formation of hydrogen and hydroxide eventually heated the alkali metal drop such that it became glowing red, and part of the metal evaporated. As a result of the reaction, a perfectly transparent drop consisting of molten hydroxide was temporarily stabilized on water through the Leidenfrost effect, bursting spectacularly after it had cooled sufficiently.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610, Prague 6, Czech Republic.
authors.forename: Philip E
authors.initials: PE
authors.lastname: Mason
authors.affiliation: Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, 38106, Braunschweig, Germany.
authors.forename: Tillmann
authors.initials: T
authors.lastname: Buttersack
authors.affiliation: Institut für Physikalische und Theoretische Chemie, Technische Universität Braunschweig, Hans-Sommer-Strasse 10, 38106, Braunschweig, Germany. s.bauerecker@tu-braunschweig.de.|Institute of Physics and Technology, National Research Tomsk Polytechnic University, Tomsk, 634050, Russia. s.bauerecker@tu-braunschweig.de.
authors.forename: Sigurd
authors.initials: S
authors.lastname: Bauerecker
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610, Prague 6, Czech Republic. Pavel.Jungwirth@uochb.cas.cz.
authors.forename: Pavel
authors.initials: P
authors.lastname: Jungwirth
keywords: Leidenfrost effect; alkali metals; solvated electrons; water