In preparation for the Birch reduction, I am trying to prepare an electride salt, $\ce{[Na(NH3)6]+, e-}.$ This salt should be brilliant blue, as far as I know, but I am getting a black sludge when adding sodium to the liquid anhydrous ammonia at −60 °C or so.

Is this because the salt is missing the electron? How do I remedy this?

  • 4
    $\begingroup$ electride salts are said to be blueish black at bulk and I beleive its solutions appear black if concentration is high enough. $\endgroup$
    – permeakra
    Jun 4, 2014 at 7:26

1 Answer 1


As long as your experimental setup did not contain any leakages or impurities through which air or moisture could have gotten into the mixture, the reaction should have worked fine under these conditions. The color of the hexaamminsodium electride solution is actually deep blue and intense, so at higher concentrations it can appear black at first sight (see picture below).

enter image description here

  • $\begingroup$ Note the blue coloration in a thin section along the rim. $\endgroup$ Jul 20, 2022 at 14:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.