Oxide and hydroxide species formed on addition of water in ambient-temperature chloroaluminate melts: An sup 17 O NMR study

The variation of the intensity of {sup 17}O NMR lines with manipulation of proton concentration and melt composition has been used to model oxy- and hydroxychloroaluminate species in the ambient-temperature molten salt system 1-ethyl-3-methylimidazolium chloride/aluminum chloride. It is concluded that the most probably oxychloroaluminate species in acidic melts are Al{sub 3}OCl{sub 8}{sup {minus}} and either Al{sub 3}O{sub 2}Cl{sub 6}{sup {minus}} or Al{sub 2}OCl{sub 5}{sup {minus}} and the most probable hydroxychloroaluminate species are Al{sub 3}Cl{sub 9}OH{sup {minus}} and Al{sub 2}Cl{sub 6}OH{sup {minus}}, with the latter being favored. In the basic melts, the most probable oxy- and hydroxychloroaluminate species are Al{sub 2}OCl{sub 5}{sup {minus}} and Al{sub 2}Cl{sub 6}OH{sup {minus}}. 20 refs., 6 figs., 7 tabs.