We request 5 days on SANDALS to investigate the structural effect of expanded metals in the LiNa-MeNH2 system at three different concentrations. The interplay between electron-solvation and on-site trapping is of fundamental interest in studying electron correlations in solution. This proposal concerns a system known to exhibit a transition between electrolyte and metal, with an initial trapping of electron density on sodide (the unusual negative oxidation state of sodium, Na-) giving rise to metallisation at higher concentration. This alkalide-metal transition is thought to be accompanied by stark structural changes in the liquid, as with metal-ammonia solutions, but no experimental data for this is yet available.