  A very good linear correlation is found between the four-point charge radius
relation $\delta R_{2p-2n}(Z,N)$ with that of quadrupole deformation data in
even-even nuclei. This results in a further improved charge radius relation
that holds in a precision of about 5$\times 10^{-3}$ fm. Such correlations are
also seen in global nuclear models, their precisions, however, are not enough
to be consistent with the experimental data. The new relation between charge
radii and deformation of even-even nuclei can be generalized to the reduced
electric quadrupole transition probability $B(E2)$ between the first $2^+$
state and the $0^+$ ground state, and the mean lifetime $\tau$ of the first
2$^+$ state.
