The rise of an empire

New sol–gel synthetic route to transition and main-group metal oxide aerogels using inorganic salt precursors

“…[2] We postulate that the species is acidic enough to donate protons to the added propylene oxide (a well known proton scavenger used in many organic reactions). [17] The protonated propylene oxide then undergoes and irreversible ring-opening reaction with the nucleophilic anion of the Cr 3+ salt (either chloride or nitrate ion in this report). The net effect is to raise the pH of the solution slowly and homogeneously that results in the formation of aquo-hydroxy species of Cr 3+ ([Cr(OH) x (H 2 O) 6-x ] +3-x ).…”