5.3 a₀ (Bohr radius) is equal to 2.8046394196687188 Å (ångström). To convert from Bohr radius to ångström, multiply by 0.5291772489940979 or divide by 1.8897259886.
physical constant; the most probable distance between an electron and the nucleus in a nonrelativistic model of the hydrogen atom with infinitely heavy nucleus