Avogadro constant

Fundamental physical constant (symbols: L,N A) representing the molar number of entities: L = 6.022 141 79 30 × 10 23 mol −1.
Source:
CODATA 2006
PAC, 1996, 68, 957 (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 963