Silver
Silver is a chemical element with symbol Ag (from the Latin "", derived from the Proto-Indo-European "h₂erǵ": "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the Earth's crust in the pure, free elemental form ("native silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining.
Silver
By far the most important oxidation state for silver in complexes is +1. The Ag cation is diamagnetic, like its homologues Cu and Au, as all three have closed-shell electron configurations with no unpaired electrons: its complexes are colourless provided the ligands are not too easily polarized such as I. Ag forms salts with most anions, but it is reluctant to coordinate to oxygen and thus most of these salts are insoluble in water: the exceptions are the nitrate, perchlorate, and fluoride. The tetracoordinate tetrahedral aqueous ion [Ag(HO)] is known, but the characteristic geometry for the Ag cation is 2-coordinate linear. For example, silver chloride dissolves readily in excess aqueous ammonia to form [Ag(NH)]; silver salts are dissolved in photography due to the formation of the thiosulfate complex [Ag(SO)]; and cyanide extraction for silver (and gold) works by the formation of the complex [Ag(CN)]. Silver cyanide forms the linear polymer {Ag–C≡N→Ag–C≡N→}; silver thiocyanate has a similar structure, but forms a zigzag instead because of the sp-hybridized sulfur atom. Chelating ligands are unable to form linear complexes and thus silver(I) complexes with them tend to form polymers; a few exceptions exist, such as the near-tetrahedral diphosphine and diarsine complexes [Ag(L–L)].