  To elucidate the geometric structure of the putative room temperature
superconductor, carbonaceous sulfur hydride, at high pressure, we present the
results of an extensive computational structure search of bulk C-S-H at 250
gigapascals. Using the minima hopping structure prediction method coupled to
the GPU accelerated Sirius library, more than 17,000 local minima with
different stochiometries in large simulation cells were investigated. Only 24
stochiometries are favourable against elemental decomposition, all of them are
carbon doped H$_3$S crystals. The absence of van Hove singularities or similar
peaks in the electronic density of states of more than 3.000 candidate phases
rules out conventional superconductivity in C-S-H at room-temperature.
