The SI unit mole and Avogadro constant

The SI (2019) states that amount of substance is proportional to the number of entities in a sample, and the reciprocal of the proportionality factor is called the Avogadro constant N A . The SI suggests that the same approach that is used to redefine the other base units (based on the defining constants Δ ν Cs , c , h , e , k , and K cd ) is also used to redefine the mole based on N A . We contend that (i) 1 mol of all samples contains a fixed number of entities, which the SI calls the Avogadro number, (ii) amount of substance is a value on the scale of measurement defined by the mole, and (iii) the 2019 SI Avogadro number (6.022 140 76 × 10 23 ) is the established value of the 1970 SI Avogadro number, which is a constant physical quantity. The Avogadro constant is not required to define the unit mole or amount of substance.