![]() ![]() It can react with sulfur to form iridium disulfide at atmospheric pressure. Very few molten salts and halogens at a high temperature can attack iridium. Silicates or molten metals at high temperatures cannot attack iridium. Even the harshest of acids like hydrochloric acid, sulfuric, and aqua regia does not affect this element. ![]() All these Iridium properties make it resistant to deformation.Īmong all the known metals, Ir is one of the most corrosion-resistant elements found in nature. Moreover, it has a very low Poisson's ratio along with high shear modulus. ![]() The modulus of elasticity of this metal is also very high as compared to other elements. The density of iridium is 22.56g/cm 3, which makes it the densest metal after osmium. At the temperature below 0.14K, this element becomes a superconductor. The boiling point of iridium is 4428☌, the tenth highest among all the elements. Hence, it is not easy to work with this transition metal. It is hard, brittle, and has a very high melting point as compared to other metals. It is white but with a slight yellowish shade. Iridium is a member of platinum group metal and hence resembles the characteristics of platinum in many ways. The most popular primary reserves of iridium on earth are Sudbury basin, Norilsk in Russia, Bushveld igneous complex in South Africa, etc. They are impact craters, igneous deposits, and deposits reworked. Iridium is present in the earth's crust in higher concentrations in three kinds of structure. Some of the rare examples are cuproiridsite and irarsite. Very few minerals in the earth's crust contain this element in the dominant form. In all the platinum group metal, iridium is present naturally in alloys with raw copper or nickel. Generally, this element is present in nature in the form of natural alloys. However, scientists believe that it has a higher concentration in the earth's core because of its siderophile (iron-loving) character. Even the platinum metal is ten times more abundant than the Ir element. Iridium is one of the rarest metals on the earth due to its less abundance. Hence, he named it iridium after the Greek winged goddess of rainbow Iris. He conducted various experiments and found that the salts that he obtained with this metal were strongly colored. In 1803, a British scientist Smithson Tennant concluded that this residue is any new metal after analyzing it properly. Some thought that it is graphite, while others cannot make any conclusion. When the chemists dissolved platinum in aqua regia to study its properties, they observed a small amount of insoluble residue, which is dark in color. Evaporation to dryness and burning under hydrogen gas gives pure iridium.The above image shows the Iridium metal in pure form Dissolution of the oxide in regia (a mixture of hydrochloric acid, HCl, and nitric acid, HNO 3) gives a solution containing pure (NH 4) 3IrCl 6. The residue contains iridium oxide, IrO 2. The residue is melted with Na 2O 2 and extracted into water to remove ruthenium and osmium salts. The insoluble residue contains the iridium. The residue is melted with sodium bisulphate (NaHSO 4) and the resulting mixture extracted with water to give a solution containing rhodium sulphate, Rh 2(SO 4) 3. Preliminary treatment of the ore or base metal byproduct is required to remove silver, gold, palladium, and platinum. The extraction is complex because of the other metals present and only worthwhile since iridium is useful as a specialist metal and is the basis of some catalysts in industry. Sometimes extraction of the precious metals such as iridium, rhodium, platinum and palladium is the main focus of a partiular industrial operation while in other cases it is a byproduct. The industrial extraction of iridium is complex as the metal occurs in ores mixed with other metals such as rhodium, palladium, silver, platinum, and gold. Isolation: it would not normally be necessary to make a sample of iridium in the laboratory as the metal is available, at a price, commercially.
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