  We report ab-initio calculations of the superconducting properties of two
high-Tc sodalite-like clathrate yttrium hydrides, YH6 and YH10, within the
fully anisotropic ME theory, including Coulomb corrections. For both compounds
we find almost isotropic superconducting gaps, resulting from a uniform
distribution of the electron-phonon coupling over phonon modes and electronic
states of mixed Y and H character. The Coulomb screening is rather weak,
resulting in a Morel-Anderson pseudopotential mu*= 0:11, at odds with claims of
unusually large Tc in lanthanum hydrides. The corresponding critical
temperatures at 300 GPa exceed room temperature (Tc = 290 K and 310 K for YH6
and YH10), in agreement with a previous isotropic-gap calculation. The
different response of these two compounds to external pressure, along with a
comparison to low-Tc superconducting YH3, may inspire strategies to improve the
superconducting properties of this class of hydrides.
