Bulk chemical properties of new elements from one-atom-at-a-time data

Abstract

For the volatile (oxo)halides of known elements the energies of desorption from the surface of fused silica measured in radiochemical gas-solid chromatographic experiments proved close to the sublimation energies. This could hardly be expected for interaction of isolated molecules with bare surface of ionic SiO 2 . Because such regularity shows great promise for evaluation of bulk properties of transactinoid compounds we need to understand the origin of apparent inconsistency. The clue seems to be the real structure of the surface. It is initially rough (from µm down to nm scale), inherently heterogeneous at the molecular level, and contains atoms and groups with excessive energy. Exposing to ambient air produces numerous surface ≡SiOH groups. The halogenating agents employed in transactinoid studies chemically modify such surface: it gets tightly covered by halogen atoms and fragments of the agent molecule attached to the Si and O atoms. Now the molecules of new compounds cannot touch SiO 2 lattice; moreover, in some initially geometric wells (due to roughness), they get surrounded by halogen atoms bonded to the surface -the situation resembling that in their own bulk condensed phase. Hence, there must be sites with desorption energies up to the sublimation energy.

Radiochemistry

“…Two reports have appeared which discuss, gas-phase 347 and solid-state 348 investigations of trans-actinide elements, whilst more specific papers have considered the chemistry of dubnium 349 and of element 112. 350…”