This grant in the Organic Dynamics Program supports the research of Dr. Robert Squires at Purdue University. Dr. Squires will complete the development of a Flowing Afterglow-Selected Ion Flow Tube-Triple Quadrupole(FA-SIFT-TQ) apparatus which will be a powerful new tool for gas-phase ion studies. With the completion of the apparatus he will obtain new fundamental information about the structures, properties and reactivity of gas-phase ions. Several systems of interest will be studied. A new method for generating gas phase carbanions from collisionally activated carboxylates will provide the basis for studying stable alkyl anions and beta-substituted ethyl anions, for determining carbanion thermochemistry from threshold measurements and for investigating the configurational stabilities of vinyl and cyclopropyl anions. Hypervalent binary hydride anions will be explored with particular emphasis on the properties, reactivity and fluxional behavior of silicon and boron hydrides. Silicon-substituted carbenium ions will be generated and their structures and stabilities determined. Thermochemical data for reactive organic intermediates such as ylides, cycloalkenylidenes and carbenes will be determined by activation methods. The results of this gas-phase ion research should have broad significance in many areas of chemistry and physics.