The "Binding Fraction" is the ratio of the binding energy of a nucleus to the atomic mass number.
Applicable units are those of quantitykind:BindingFraction
http://encyclopedia2.thefreedictionary.com/binding+fraction
The "Binding Fraction" is the ratio of the binding energy of a nucleus to the atomic mass number.
$b = \frac{B_r}{A}$, where $B_r$ is the relative mass defect and $A$ is the nucleon number.
http://www.iso.org/iso/catalogue_detail?csnumber=31895