  In recent years, there has been a fervent search for room-temperature
superconductivity within the binary hydrides. However, as the number of
untested compounds dwindled, it became natural to begin searching within the
ternary hydrides. This led to the controversial discovery of room-temperature
superconductivity at only 1GPa in nitrogen-doped lutetium hydride
[Dasenbrock-Gammon et al., Nature 615, 244 (2023)] and consequently provided
much impetus for the synthesis of nitrogen-based ternary hydrides. Here, we
report the synthesis of stable trigonal LuH$_3$ by hydrogenating pure lutetium
which was subsequently pressurised to $\sim$2GPa in a dilute-N$_2$/He-rich
pressure medium. Raman spectroscopy and x-ray diffraction were used to
characterise the structures throughout. After depressurising, energy-dispersive
and wavelength-dispersive X-ray spectroscopies characterised the final
compound. Though our compound under pressure exhibits similar structural
behaviour to the Dasenbrock-Gammon et al. sample, we do not observe any
nitrogen within the structure of the recovered sample at ambient pressure. We
observe two cubic structures under pressure that simultaneously explain the
X-ray diffraction and Raman spectra observed: the first corresponds well to
$Fm\overline{3}m$ LuH$_{2+x}$, whilst the latter is an $Ia\overline{3}$-type
structure.
