For alkali metals in liquid ammonia, the solution is blue when dilute and copper-colored when more concentrated (> 3 molar).
The blue colour of the solution is due to ammoniated electrons, which absorb energy in the visible region of light.
The reaction is reversible: evaporation of the ammonia solution produces a film of metallic sodium.
Alkali metals also dissolve in some small primary amines, such as methylamine and ethylamine[7] and hexamethylphosphoramide, forming blue solutions.
Tetrahydrofuran (THF) dissolves alkali metal, but a Birch reduction (see § Applications) analogue does not proceed without a diamine ligand.
This implies their possible existence in the upper atmosphere of Earth and involvement in nucleation and aerosol formation.
[12] It's standard electrode potential value is -2.88 V.[13] The equivalent conductivity of 177 Mho cm2 is similar to that of hydroxide ion.
[16] Solvated electrons are involved in electrode processes, a broad area with many technical applications (electrosynthesis, electroplating, electrowinning).
[17] An example of this is the intercalation of graphite with potassium and ammonia, which is then exfoliated by spontaneous dissolution in THF to produce a graphenide solution.
[26] They noted based on absorption spectra that different metals and different solvents (methylamine, ethylamine) produce the same blue color, attributed to a common species, the solvated electron.