  Negative thermal expansion (NTE) describes the anomalous propensity of
materials to shrink when heated. Since its discovery, the NTE effect has been
found in a wide variety of materials with an array of magnetic, electronic and
structural properties. In some cases, the NTE originates from phase competition
arising from the electronic or magnetic degrees of freedom but we here focus on
a particular class of NTE which originates from intrinsic dynamical origins
related to the lattice degrees of freedom, a property we term
\textit{structural} negative thermal expansion (SNTE). Here we review some
select cases of NTE which strictly arise from anharmonic phonon dynamics, with
a focus on open perovskite lattices. We find that NTE is often present close in
proximity to competing structural phases, with structural phase transition
lines terminating near $T$=0 K yielding the most superlative displays of the
SNTE effect. We further provide a theoretical model to make precise the
proposed relationship among the signature behavior of SNTE, the proximity of
these systems to structural quantum phase transitions and the effects of phase
fluctuations near these unique regions of the structural phase diagram. The
effects of compositional disorder on NTE and structural phase stability in
perovskites are discussed.
