as.ta.tine
n.Symbol At （名词）符号 At A highly unstable radioactive element, the heaviest of the halogen series, that resembles iodine in solution. Its longest lived isotope has a mass number of 20 and has a half-life of 8.3 hours. Atomic number 85; melting point 302=C; boiling point 337=C; valence probably , 3, 5, 7.See table at element 砹：极不稳定放射性元素，在卤族元素比重最大，在溶解状态与碘相象，它最长周期的同位素原子量为20，半衰期为8.3小时。原子序数85；溶点302=C；沸点337=C；化合价可能为、3、5、7参见 element
来源：Greek astatos [unstable] * see astasia 希腊语 astatos [不稳定的] *参见 astasia-ine 2-ine2
