稀有元素





Confusion grey.svg  提示：本条目的主题不是微量元素。


稀有元素是自然界中储量、分布稀少（一般地壳丰度为100ppm以下）且人类应用较少的元素总称。稀有元素常用来制造特种金属材料，如特种钢、合金等，在飞机、火箭、原子能等工业领域属于关键性材料。常用的稀有金属有锂、钛、镭等。



在不同领域中的含义


在分析化學中「痕量元素」指的是「某一元素在樣本中的濃度小於100ppm需測量到原子的規模」或是「這個元素在每公克的樣本中含量少於100微克(µg，1µg=0.000001g)。


在生物化學上「痕量元素」指的是：某種化學元素只需要微小的量，就能使組織適當的成長、發展、完成組織的生理機能。在生物化學上「痕量元素」有時也指的是微量營養素。[1]


在地球化學上「痕量元素」某種化學元素是在岩石中的含量少於1000ppm或0.1%，這術語主要用於「火成岩岩石學」上。



参见



  • 主要元素

  • 營養素

  • 放射性同位素

  • 豐度



参考资料





  1. ^ H. J. M. Bowen, Trace Elements in Biochemistry. Academic Press, 1966. (2nd edition, 1976.) See also List of micronutrients.













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