絛蟲
銀(silver)
金屬化學元素，過渡元素之一，化學符號Ag，原子序數47。是一種色澤白亮的貴金屬，其價值之一就在於它漂亮的外觀。它的導電能力是所有金屬中最高的。在週期表中處於銅和金之間，在許多效能上銀也在銅與金的中間。以小量廣泛分佈於自然界，可以呈天然金屬的狀態，也可存在於礦石中，通常是生產銅與鉛的副產品。1960年代工業上對銀的需求已壓倒製作銀錠和錢幣的用途，尤其在攝影術中要求使用銀。它還用於印製電路、電子導體以及電接觸。在將乙烯轉化成氧化乙烯（許多有機化合物的前身）的過程中要以銀作催化劑。它還用於標準純銀合金（92.5%的銀，7.5%的銅），鍍銀的銀器、裝飾品和首飾仍是它的重要用途；首飾中使用的黃金含25%的銀，鑲牙的金中含10%的銀。補牙用的銀是銀和汞的汞齊。銀在化合物中，最重要的是硝酸銀中的原子價是1。銀的氯化物、溴化物和碘化物都用於攝影，銀的碘化物還用作雲的催化劑。
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.