  Satterthwaite and Toepke (1970 Phys. Rev. Lett. 25 741) predicted
high-temperature superconductivity in hydrogen-rich metallic alloys, based on
an idea that these compounds should exhibit high Debye frequency of the proton
lattice, which boosts the superconducting transition temperature, Tc. The idea
has got full confirmation more than four decades later when Drozdov et al (2015
Nature 525 73) experimentally discovered near-room-temperature
superconductivity in highly-compressed sulphur superhydride, H3S. To date, more
than a dozen of high-temperature hydrogen-rich superconducting phases in Ba-H,
Pr-H, P-H, Pt-H, Ce-H, Th-H, S-H, Y-H, La-H, and (La,Y)-H systems have been
synthesized and, recently, Hong et al (2021 arXiv:2101.02846) reported on the
discovery of C2/m-SnH12 phase with superconducting transition temperature of Tc
~ 70 K. Here we analyse the magnetoresistance data, R(T,B), of C2/m-SnH12 phase
and report that this superhydride exhibits the ground state superconducting gap
of $\Delta$(0) = 9.2 meV, the ratio of 2$\Delta$(0)/k$_B$Tc = 3.3, and 0.010 <
Tc/Tf < 0.014 (where Tf is the Fermi temperature) and, thus, C2/m-SnH12 falls
into unconventional superconductors band in the Uemura plot.
