172Yb has 70 protons and 102 neutrons.
172Yb is a stable isotope.
The mass excess of 172Yb is -59255.456 with an uncertainty of ±0.014.
The mass was measured using a Penning Trap and the related equations include:
Influence Equations
100% 172Yb-132Xe1.303 1
Reference
1. R. Rana, M. Hocker, E.G. Myers (2012) Atomic masses of strontium and ytterbium
Physical Review A 86(5)
https://journals.aps.org/pra/abstract/10.1103/PhysRevA.86.050502