Antimony, metal element, element symbol Sb, atomic number 5 1. It is a nonmetal with metallic luster, which mainly exists in the sulfide mineral stibnite in nature. At present, it is known that antimony compounds were used as cosmetics in ancient times, and metallic antimony was also recorded in ancient times, but it was mistaken for lead at that time. About17th century, people know that antimony is a chemical element.

A silvery shiny hard brittle metal (often made into strips, blocks, powders and other shapes). Has a scale-like crystal structure. It gradually loses its luster in humid air and burns into white antimony oxide when exposed to high heat. Soluble in aqua regia and concentrated sulfuric acid. Relative density 6.68, melting point 630℃, boiling point 1635℃, atomic radius 1.28? , electronegativity 2.2.

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Antimony can form a versatile alloy with lead, and the hardness and mechanical strength of this alloy are higher than that of antimony. In most cases where lead is used, different amounts of antimony are added to make alloys.

In lead-acid batteries, this additive can change the electrode performance and reduce the generation of hydrogen as a by-product during discharge. Antimony is also used in antifriction alloys, bullets, lead bullets, steel wire shells, lead alloys, solder, lead-tin-antimony alloys and alloys with less tin, and is used to harden organs.

The main use of antimony is that its oxide antimony trioxide is used to make refractories. Except for halogen-containing polymer flame retardants, it is almost always used with halide flame retardants.

The process of antimony trioxide forming antimony halide can slow down combustion, which is why it has flame retardant effect. These compounds react with hydrogen atoms, oxygen atoms and hydroxyl radicals, and finally put out the fire. These flame retardants are commercially used in children's clothing, toys, aircraft and car seat covers.

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