Chromium Amalgams

A Chromium Amalgams of composition Hg₃Cr may be prepared by the electrolysis of a solution of chromic chloride in dilute hydrochloric acid with a powerful current, the cathode being of mercury and the anode of platinum. The Chromium Amalgams is solid, soft, brilliant, and only slightly acted on by air. When heated, it loses mercury without melting and oxidises rapidly. When subjected to a pressure of 200 kilos, per sq. cm., it loses mercury and yields another amalgam of composition HgCr. This is brilliant, harder than the first, and more readily changes in air. Both decompose on distilling in a vacuum below 300° C., yielding chromium which is pyrophoric at ordinary temperatures.