Magnesium precipitation from high-lithium

Highly reactive calcium can be readily prepared by the reduction of calcium halides in tetrahydrofuran solution with preformed lithium biphenylide under an argon atmosphere at room temperature.5 This colored calcium species seems to be reasonably soluble in THF. However, the reactive calcium complex prepared from preformed lithium naphthalenide was insoluble in THF solution and precipitated out of solution to give a highly reactive black solid. The exact nature of this black calcium complex has not been determined. Acid hydrolysis of the black material releases naphthalene as well as THF. Accordingly, the most likely structure of the black material is a Ca-naphthalene-THF complex similar in nature to the soluble magnesium-anthracene complex recently reported.6... 

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