  Nuclear contact is a key quantity to describe the nucleon-nucleon short-range
correlations (SRCs). While they have been determined by electron scattering
experiments for selected stable nuclei, nuclear contacts are largely unknown
for unstable nuclei. In this work, we study nuclear contacts for a number of
nuclei in the vicinity of the doubly magic $^{132}$Sn from the theoretical
perspective, with special emphasis on unstable nuclei. We find that the
proton-proton contact generally gets suppressed by the excess neutrons for the
Sn isotopes, resembling the suppression of $\alpha$-cluster formation reported
recently for the same isotopic chain [J. Tanaka $\textit{et al}.$, Science
$\textbf{371}$, 260 (2021)]. This indicates a hidden universal aspect of SRCs
and $\alpha$ clustering, two different kinds of nuclear correlations.
Meanwhile, a linear relation is found between the proton-proton contact and the
proton number for the $N=82$ isotones. Our results can be helpful for future
experimental studies of SRCs in unstable nuclei at advanced facilities
worldwide.
