  Room-temperature superconductivity was recently discovered in carbonaceous
sulfur hydride (C-S-H) close to 3\,Mbar. We report significant differences in
the superconducting response of C-S-H, with a maximum $T_{C}$ of 191(1)\,K,
below a 1\,Mbar. Variations in intensity of the C-H Raman modes reveal carbon
content can vary between crystals synthesized with the same photo-induced
method. Synchrotron single crystal x-ray diffraction identifies polymorphism
with increasing degrees of covalency. These unique metastable states are highly
sensitive to thermodynamic pathways.
