# Is there a notion of generalized acidity for lithium ions?

From my understanding, the basic notions of acidity can be explained by considering a cup of pure water, and then adding a substance to it which creates either free $$\ce{H+}$$, or free $$\ce{H3O+}$$ and $$\ce{H5O2+}$$ etc...

And these ions are free to react and give rise to what we consider acidic behavior. The classic example is hydrogen chloride characterized with the following reaction

$$\ce{HCl +H2O = H3O+ + Cl-}$$

Whereas $$\ce{H3O+}$$ is our famous hydrochloric acid.

I wonder if it is possible for an analogous reaction to happen with other polar molecules. For example liquid $$\ce{Li2O}$$ (I believe it melts around 1438 Celsius) should be a polar liquid for the same reasons that $$\ce{H2O}$$ is (though maybe not as strongly polar), and therefore: $$\ce{LiCl}$$ should dissolve in molten $$\ce{Li2O}$$ to create positive charged lithium ion species such as $$\ce{Li3O+}$$. Which ought to function as an "acid" of sorts, in that they react with most thing which are dissolved/reacted by hydrochloric acid by acting as a positive charge donor (clearly not a proton donor since we are using lithium and not hydrogen to do the deed here)

Is my line of reasoning sound and has this been experimentally detected before?

• I'm not sure if you want more then that Li cation is obviously Lewis acid Dec 22 '20 at 2:23
• (so I can get the terminology right) our $\text{Li}_2 \text{O}$ fluid with dissolved $\text{Li}\text{Cl}$ is a Lewis acid? Dec 22 '20 at 2:25
• $\ce{Li+}$ is a Lewis acid that might coordinate to $\ce{Li2O}$ base forming an adduct. I highly doubt you can get much $\ce{Li2O}$ molecules outside of vapor phase, thogh. Dec 22 '20 at 2:30

A complex of lithium ion with lithium hudroxide is known as the salt $$\ce{[Li2OH]^+[ClO4]^-}$$ [1]. As with the hydronium salt, this requires an essentially nonbasic counterion; with a chloride counterion a double salt is obtained with no evidence of a complex cation. From the abstract (some evident faults in translation from Russian have been corrected):