Sackur–Tetrode constant

https://doi.org/10.1351/goldbook.S05442
Fundamental physical constant representing the translational contribution to molar entropy; S 0 R =-1.151 693 21 at 1 K and standard pressure of 100 kPa, where R is the gas constant.
Source:
CODATA Bull. 1986, 63, 1 (https://doi.org/10.6028/jres.092.010)