  YbBiPt is a heavy-fermion compound possessing significant short-range
antiferromagnetic correlations below a temperature of $T^{\textrm{*}}=0.7$ K,
fragile antiferromagnetic order below $T_{\rm{N}}=0.4$ K, a Kondo temperature
of $T_{\textrm{K}} \approx1$ K, and crystalline-electric-field splitting on the
order of $E/k_{\textrm{B}}=1\,\textrm{-}\,10$ K. Whereas the compound has a
face-centered-cubic lattice at ambient temperature, certain experimental data,
particularly those from studies aimed at determining its
crystalline-electric-field scheme, suggest that the lattice distorts at lower
temperature. Here, we present results from high-resolution, high-energy x-ray
diffraction experiments which show that, within our experimental resolution of
$\approx6\,\textrm{-}\,10\times10^{-5}$ \AA, no structural phase transition
occurs between $T=1.5$ and $50$ K. In combination with results from dilatometry
measurements, we further show that the compound's thermal expansion has a
minimum at $\approx18$ K and a region of negative thermal expansion for
$9<T<18$ K. Despite diffraction patterns taken at $1.6$ K which indicate that
the lattice is face-centered cubic and that the Yb resides on a
crystallographic site with cubic point symmetry, we demonstrate that the linear
thermal expansion may be modeled using crystalline-electric-field level schemes
appropriate for Yb$^{3+}$ residing on a site with either cubic or less than
cubic point symmetry.
