Element name: gold chemical element symbol: Au CASNo. : 7440-57-5[ 1] Metal density:19.3g/cm3; Specific heat capacity: 0.13kj/(kg k) atomic number: 79 nuclear charge number: 79 extranuclear electrons number: 79 ordinary oxidation number:+1, +3 atomic radius: 134 M+ ion radius: 137 M3+. : 10.2 element content in the sun: 0.00000 1‰ element content in seawater: 0.000000 1 ‰ crustal content: 0.00001‰ oxidation state: main Au+3 other Au-60. O3, the molecular formula of hydrate is Au? O3 3H？ o； Molecular weight 495.98; Gold content is 77.0%; Appearance brown powder; Storage method: dry and sealed storage at room temperature. Chemical characteristics: When heated, oxygen is released to generate elemental gold. 2au? O3 = 4Au + 3O？ ↑ Method: 0.2au (OH) 3 = Au can be obtained by heating gold hydroxide at high temperature. O3 + 3H？ O

Gold is a metallic element with chemical symbol Au and atomic number 79.

The simple substance (free form) of gold, commonly known as gold, is a popular precious metal, which has been used as currency, preservation and jewelry for many centuries. In nature, gold exists in the form of simple substance in gold nuggets or rocks, underground veins and alluvium. Gold is also one of the currency metals. Gold, a simple substance, is solid at room temperature, with high density, softness, brightness, corrosion resistance and the highest ductility and ductility among known metals.

Gold is a transition metal, which can form trivalent and monovalent positive ions after dissolution. Gold will not react with most chemicals, but will be corroded by chlorine, fluorine, aqua regia and cyanide. Gold can be dissolved by mercury to form amalgam (but this is not a chemical reaction); Nitric acid can dissolve silver and base metals, but not gold. The above two properties become the basis of gold refining technology, which are called "separate casting" and "separate casting" respectively.