Important: Safety Warning
This page describes trade processes that use dangerously toxic materials such as cyanide solutions, mercury amalgams, or strong acids. These processes require training, equipment, and precautions far beyond what the text describes.
This information has been left in for historical purposes but should not be acted upon.
Chloride
Compounds of great importance are formed by a combination of chlorine with metals and other substances. Most of the chlorides are soluble in water, and metals enter into as many combinations with chlorine as they do with oxygen. Chlorides melt at ordinary temperatures, and are more easily dissolved and fused than are their corresponding acids. Chlorides usually decompose when heated in a current of hydrogen, the result being hydrochloric acid and the pure metal. Simple ignition will decompose chlorides of noble metals, leaving the uncombined metal. If chlorides are heated with black oxide of manganese and sulphuric acid, the chlorine is eliminated. Chlorine abounds in the mineral world, chiefly in the metal sodium, in salt, etc., and is prepared by heating black oxide of manganese with hydrochloric acid--which forms a yellowish transparent gas 2 1/2 times heavier than air. Under a pressure of four atmospheres it is condensed into a liquid slightly heavier than water and which remains unfrozen at 220 deg. This gas unites with oxygen to form five compounds: with hydrogen it forms hydrochloric acid; with nitrogen, an explosive of great power, called per-chloride of nitrogen; and it forms several chlorides with carbon.