History 

　　Chemical Symbols–Part of Chemical Language 

　　Chemical nomenclature and symbols are two of the most important parts of the language of chemistry. Early nomenclature was completely empirical. As aresult, the confusion arose between substance names and their chemical properties. For example, “oil of vitriol” was the name of sulfuric acid, which is not an oil at all. By the mid-18th century, a large number of new substances were discovered thanks to the rapid development of chemistry. The old no-menclature could no longer meet the needs of chemist. Finally, at the end of 18th century, Antoine Lavoisier started chemical revolution, replacing the old empirical nomenclature with a new one based on chemical composition and properties. 

　　The earliest use of chemical symbols could be traced back to ancient Egypt glyphs and Greek manuscripts. Experts think that a small number of chemical symbols could be evolved from Egypt glyphs; a few others came from Greek manuscripts. The majority symbols used by al-chemists from the 17th to 18th century were created by the alchemists themselves. Some of the alchemy symbols were pictorial representations of the chemical apparatuses, while others were just random graphical constructions. The main purpose of using symbols was to reduce texts and improve the reading speed of alchemy books. However, many alchemists believed that the secrets of philosopher’s stone were hidden within the symbols and worked endlessly to decipher them. Also, alchemy symbols could also cause confusion: some symbols with dif-ferent meanings looked very similar, and same symbols might be used to indicate different meanings by different alchemists. Because of the mystical and confusing nature of alchemy symbols, some scholars created new symbol systems to replace them. Lavoisier proposed that chemical information should also be encoded in symbols. In 1808, John Dalton published a new symbol system which was an important achievement. Dalton designed a circular symbol for each element known in his time. In his system, a compound was a graphic assembly of the element symbols based on their proportion. However, Dalton’s symbols were not easy to write and remember, just like old alchemy symbols. We should thank Jacob Berzelius for the chemical symbol system we are using today (e.g. Na stands for sodium, NaCl for salt, and H2O for water). Although Berzelius was not the first person who used the initial letters of element names as symbols, he was the first to apply this system to all the chemical substances known at his time.

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