## inertial defect

https://doi.org/10.1351/goldbook.I03028
Difference of principal @[email protected] $$\mathit{\Delta} = I_{C} - I_{A} - I_{B}$$. For planar molecules it is close to zero and for non-planar molecules it is negative.
Source:
Green Book, 2nd ed., p. 23 [Terms] [Book]