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Osmium is a hard, brittle, blue-gray metal, and the densest stable element—about twice as dense as lead. The density of osmium is slightly greater than that of iridium ; the two are so similar (22.587 versus 22.562 g/cm 3 at 20 °C) that each was at one time considered to be the densest element.
Osmium is a hard but brittle metal that remains lustrous even at high temperatures. It has a very low compressibility. Correspondingly, its bulk modulus is extremely high, reported between 395 and 462 GPa, which rivals that of diamond (443 GPa). The hardness of osmium is moderately high at 4 GPa.
The chemical elements can be broadly divided into metals, metalloids, and nonmetals according to their shared physical and chemical properties.All elemental metals have a shiny appearance (at least when freshly polished); are good conductors of heat and electricity; form alloys with other metallic elements; and have at least one basic oxide.
The ductile failure model of Lynch [17] and Popovich [18] predicted that adsorption of the liquid metal leads to the weakening of atomic bonds and nucleation of dislocations, which move under stress, pile up and work harden the solid. Also, dissolution helps in the nucleation of voids which grow under stress and cause ductile failure.
Most definitions of the term 'refractory metals' list the extraordinarily high melting point as a key requirement for inclusion. By one definition, a melting point above 4,000 °F (2,200 °C) is necessary to qualify, which includes iridium, osmium, niobium, molybdenum, tantalum, tungsten, rhenium, rhodium, ruthenium and hafnium. [2]
The common oxide of carbon (CO 2) is a medium-strength acidic oxide. Silicon has a blue-grey metallic lustre. Silicon is a metallic-looking relatively unreactive solid with a density of 2.3290 g/cm 3, and is hard (MH 6.5) and brittle. It melts at 1414 °C (cf. steel ~1370 °C) and boils at 3265 °C. Silicon has a diamond cubic structure (CN 4).
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Some metals that are generally described as ductile include gold and copper, while platinum is the most ductile of all metals in pure form. [4] However, not all metals experience ductile failure as some can be characterized with brittle failure like cast iron. Polymers generally can be viewed as ductile materials as they typically allow for ...