In an acid solution, Co (II) is more stable than Co (III). The oxidation state free energy diagram shows that the most common and important chemical compounds of cobalt are formed in +2 and +3 oxidation states. The metal cobalt reacts with most of the halogens like fluorine, chlorine, bromine, and other non-metals like boron, carbon, phosphorus, and sulfur on heating.It is a ferromagnetic metal with a high curie point (1121 ☌).The hardness and tensile strength of the metal are greater than those of steel.Cobalt is a lustrous silvery metal with a bluish tinge.It is a member of d-block elements or transition metals. Some important physical and atomic properties of cobalt are given below the table, CobaltĬobalt is placed on period-4 and group-9 on the periodic table with group members rhodium and iridium. Finely divided metallic cobalt is pyrophoric like iron but the compact metal is not attacked by air or water at ordinary temperatures. The +2 and +3 oxidation number or state is important to derive different types of chemical bonding and compounds of metal.Ĭo (II) is more stable than Co (III) in acid solutions. The hexagonal crystal lattice cobalt has a valence shell electronic configuration 3d 7 4s 2. A small reserve of metal is found in Australia and Russian countries. South Africa and Canada are the main producers of cobalt. Besides arsenic, sulfur and iron contain 4 to 10 percent of cobalt, and a varying amount of silver, copper, and lead. The principal minerals of cobalt are arsenides and sulfides like smaltite, CoAs 2, erythrite, Co 3(AsO 4) 2. It is the thirtieth most abundant element of all known elements that are found mainly with nickel and arsenic. Where is cobalt found?Ĭobalt is less common among the first transition metals except for scandium. The identity of cobalt as a new metal was established around 1780 by T Bergmann and other scientists. Brandit describes six semi-metals like mercury, bismuth, zinc, antimony, cobalt, and arsenic.īefore 1776, many scientists believed that the element was a compound of iron and arsenic. Brandt analyzed some specimens of the cobold and wrote about a new semi-metal which he named cobold. The name of the metal given from the German word cobold means evil spirit or goblin. The history of the discovery of cobalt may be started with its naming. It does not attack by aqueous alkalies like NaOH or KOH but is readily dissolved in fused KOH at 550 ☌. The metal is less readily dissolved in mineral acids like nitric acid and sulfuric acid. The hardness and tensile strength of cobalt are higher than steel. It is used in making different types of alloys, and large quantities of its compounds are used in the glass and ceramic industries.
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