Lead Tetraethyl, Pb(C₂H₅)₄

Lead Tetraethyl (Tetraethide), Pb(C₂H₅)₄, is obtained from lead chloride and zinc methyl, or by means of the Grignard reaction, thus:

2PbCl₂ + 4C₂H₅MgI = Pb(C₂H₅)₄ + Pb + 4MgClI.

This compound is a liquid which cannot be distilled under ordinary pressure without decomposition, but boils at 152° C. under 190 mm. pressure. It has a density of 1.62. The lowering of freezing-point of ethylene bromide by lead tetraethyl has been determined by Ghira.

The chloride Pb(C₂H₅)₃Cl, formed by the action of hydrogen chloride on the tetraethyl, crystallises in needles; and the iodide results from the action of iodine on the same compound, and of magnesium ethyliodide on lead chloride. These halides are salts, derived from the base Pb(C₂H₅)₃OH, which is formed by treating the iodide with moist silver oxide or distilling the chloride with potash. This base crystallises in needles, which are slightly soluble in water, have a strongly alkaline reaction, absorb carbon dioxide from the air, and combine with acids to form crystalline salts; e.g. the sulphate [Pb(C₂H₅)₃]₂SO₄, which is slightly soluble in water.