Avogadro constant.

value = avogadro
[value,sigma] = avogadro

amu returns the Avogadro constant, i.e., the number of parts in a mol, in value and the standard deviation in sigma (if two output arguments are specified).

The value and the standard deviation are taken from the 2018 CODATA collection of recommended values.

amu, angstrom, barn, bmagn, bohrrad, boltzm, clight, echarge, emass, eps0, evolt, faraday, gammae, gfree, hartree, hbar, molgas, mu0, nmagn, nmass, planck, pmass, rydberg