Lithium Amide (LiNH2) under Pressure

Lithium Amide (LiNH2) under Pressure

Prasad, Dasari, Neil W. Ashcroft, and Roald Hoffmann
The Journal of Physical Chemistry A 116, no. 40 (2012): 10027-10036
https://doi.org/10.1021/jp3078387

“Things change, often drastically so, when one applies external pressure. Methane (CH4) and ammonia (NH3) crystallize at about 1−2 GPa at 298 K but retain their respective molecular structures, along with orientational disordering. At high pressure and temperatures (19 GPa and 2000−3000 K), methane becomes thermodynamically unstable with respect to heavier hydrocarbons, while ammonia transforms (in calculations) into an ionic solid (ammonium amide, NH4+ NH2−) at 90 GPa. Water, isoelectronic to the NH2− anion, takes a very different path. It loses its well-defined molecular and hydrogen-bonded structure above 60 GPa, forming networks with linear O···H···O symmetrical bridging bonds.”

— Dasari LVK Prasad et al.