Copper. Co; at. wt. 63.54; at. no. 29; valence 1-2. Two isotopes with at. wts. 63 and 65. One of the earliest known metals. Yearly world production more than 2 million metric tons.

Reddish, lustrous, ductile, malleable metals; in the form of ingots, sheets, wire or powder. Becomes dull when exposed to air. In moist air gradually becomes coated with green basic carbonate. d. 8.94. m. 1083°. b. 2325°.

Mohs' hardness 3.0. Specific resistance 1.682 X 10^–6 ohms / cm. Electrolytic potential 0.344 volt. Very slowly attacked by cold hydrochloric or diluted sulfuric acid; readily dissolved by dil. nitric acid and attacked by hot concentr. H₂SO₄. It is dissolved by hot concentr. hydrobromic acid. It is also attacked by acetic and other organic acids. Slowly soluble in ammonia water.

Water-soluble cupric salts yield with sod. hydroxide a bluish-green precipitate of cupric hydroxide which is changed to black cupric oxide on warming. Potassium ferrocyanide produces a brownish-red precipitate of copper ferrocyanide. Hydrogen sulfide produces in acid solns. a black precipitate of cupric sulfide which is soluble in soln. of sod. cyanide. Aluminum, iron or zinc precipitate metallic copper from its solns.

Use: Manuf. bronzes, brass, other copper alloys, electrical conductors, ammunition, copper salts, works of art.

Grades available: Reagent, technical.

(Mineral deficiencies in Plants)

Although specific functions have not been Determined for this element, here again the evidence points to their roles as catalysts and regulators. Like iron and manganese, these two elements have been suggested as of importance in oxidation- reduction reactions. Deficiencies of both are associated with chlorosis and a serious general collapse of vital growth processes. Since catalysts are not used up in the chemical reactions which they promote, we can understand how it comes about that quite small or even minute of the "trace elements", iron, manganese, boron, zinc and copper, may never the less be essential to the plant's health and growth.

Doctors at Loyola University Medical School in Chicago and the Carl Pheiffer Treatment Center have reported that violent males between the ages of 3 and 18 commonly have elevated copper and reduced zinc blood levels when compared to nonviolent males. Depression and schizophrenia also have links to high copper levels.