University Chemistry ›› 2020, Vol. 35 ›› Issue (8): 67-74.doi: 10.3866/PKU.DXHX201910029

Special Issue:

• Survey of Chemistry • Previous Articles     Next Articles

New Definition of Mole and the Accurate Avogadro Constant

Lingxiang Gao(), Shuying Zhang, Weiqiang Zhang, Quanguo Zhai, Mancheng Hu, Shengli Gao   

  • Received:2019-10-15 Accepted:2020-01-02 Published:2020-02-21
  • Contact: Lingxiang Gao
  • Supported by:


The new standard for international SI units was officially implemented this year and the definitions of the SI basic units, such as mole, will be changed to constants. In this paper, the Avogadro's constant and the principle of molar mass are briefly reviewed, and we focus on the concept of Mole's new definition and how to accurately measure Avogadro constant, as well as the development of atomic weight precision measurement, nano-scale precision measurement, materials preparation and characterization technologies. The new definition of Mole will affect every undergraduate of chemistry because it can better reflect the relationship between scientific methods and scientific thinking and chemical knowledge. It can be anticipated that the new definition of Mole will soon have a huge impact on the teaching of inorganic chemistry, analytical chemistry and physical chemistry. This recount is naturally important to improve the scientific thinking and research quality of undergraduates.

Key words: Mole, Avogadro constant, Atomic mass, Monocrystalline silicon, Metrology