The metal-amines formed by dissolution of alkali or electropositive metals in anhydrous ammonia has long been known to yield a concentration-dependent metal-insulator transition (MIT). In the concentrated regime, the metallic systems exhibit a large volumetric expansion (hence their moniker of ‘expanded metals’) to give a low and tunable electron density in the liquid state. In addition to ammonia, lithium metal also demonstrates a large solubility in methylamine, but undergoes its MIT at a higher concentration of metal. &lt;!--[endif]----&gt;Here we report a homogenous expanded metal containing two equimolar amine solvents: the Li-NH3-MeNH2 system. The phase behavior and magnetic measurements of Li-NH3-MeNH2 suggest that it is just on the metallic side of the MIT, as compared to the single-amine analogues. We discuss the local structure of the liquid metal formed at 20 mole-percent lithium, Li(NH3)n(MeNH2)m [n+m=4] as determined from multi-isotope neutron scattering, and find that the liquid is strongly correlated over a several angstrom lengthscale. The local structure about lithium is unique amongst the expanded metal-amines, as too is the manner in which excess electron density is accommodated in the liquid. &lt;!--![endif]----&gt;

Further disordering for expanded metals: The liquid Li-NH3-MeNH2 system

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.