银

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银(silver)

金属化学元素，过渡元素之一，化学符号Ag，原子序数47。是一种色泽白亮的贵金属，其价值之一就在於它漂亮的外观。它的导电能力是所有金属中最高的。在周期表中处於铜和金之间，在许多性能上银也在铜与金的中间。以小量广泛分布於自然界，可以呈天然金属的状态，也可存在於矿石中，通常是生产铜与铅的副产品。1960年代工业上对银的需求已压倒制作银锭和钱币的用途，尤其在摄影术中要求使用银。它还用於印制电路、电子导体以及电接触。在将乙烯转化成氧化乙烯（许多有机化合物的前身）的过程中要以银作催化剂。它还用於标准纯银合金（92.5%的银，7.5%的铜），镀银的银器、装饰品和首饰仍是它的重要用途；首饰中使用的黄金含25%的银，镶牙的金中含10%的银。补牙用的银是银和汞的汞齐。银在化合物中，最重要的是硝酸银中的原子价是1。银的氯化物、溴化物和碘化物都用於摄影，银的碘化物还用作云的催化剂。

English version：

silver

Metallic chemical element, one of the transition elements, chemical symbol Ag, atomic number 47. It is a white, lustrous precious metal, valued for its beauty. It is also valued for its electrical conductivity, which is the highest of any metal. Between copper and gold in the periodic table, it is intermediate between them in many properties. Widely distributed in nature in small amounts, as the native metal and in ores, it is usually recovered as a by-product of copper and lead production. Its use in bullion and coins was overtaken in the 1960s by demand for industrial purposes, especially photography. It is also used in printed electrical circuits, electronic conductors, and contacts. It is the catalyst for converting ethylene to ethylene oxide, the precursor of many organic chemicals. Its use in alloys in sterling (92.5% silver, 7.5% copper) and plated silverware, ornaments, and jewelry remains important; yellow gold used in jewelry is 25% silver, and gold dental alloys are about 10% silver. Silver dental fillings are an amalgam of silver and mercury. Silver in compounds, the most important of which is silver nitrate, has valence 1. Its chloride, bromide, and iodide are used in photography and its iodide in cloud seeding.