nitrogen

nitrogen
[ˈnʌɪtrədʒ(ə)n]
noun

[mass noun]the chemical element of atomic number 7, a colourless, odourless unreactive gas that forms about 78 per cent of the earth's atmosphere. Liquid nitrogen (made by distilling liquid air) boils at 77.4 kelvins (-195.8°C) and is used as a coolant(Symbol: N)
（化学元素）氮(符号：N)
Nitrogen forms many important compounds including nitric acid, ammonia, and nitrogenous fertilizers, and many biological molecules such as amino acids and proteins

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