  The low-temperature specific heat of a superconductor Mo3Sb7 with T_c = 2.25
(0.05) K has been measured in magnetic fields up to 5 T. In the normal state,
the electronic specific heat coefficient gamma_n, and the Debye temperature
Theta_D are found to be 34.5(2) mJ/molK^2 and 283(5) K, respectively. The
enhanced gamma_n value is interpreted due to a narrow Mo-4d band pinned at the
Fermi level. The electronic specific heat in the superconducting state can be
analyzed in terms a phenomenological two BCS-like gap model with the gap widths
2Delta_1/k_BT_c = 4.0 and 2Delta_2/k_BT_c = 2.5, and relative weights of the
mole electronic heat coefficients gamma_1/gamma_n = 0.7 and gamma_2/gamma_n =
0.3. Some characteristic thermodynamic parameters for the studied
superconductor, like the specific heat jump at T_c, DeltaC_p(T_c)/gamma_nT_c,
the electron-phonon coupling constant,lambda_eph, the upper H_c2 and
thermodynamic critical H_c0 fields, the penetration depth, lambda, coherence
length xi, and the Ginzburg-Landau parameter kappa are evaluated. The estimated
values of parameters like 2Delta/k_BT_c, DeltaC_p(T_c)/gamma_nT_c, N(E_F), and
lambda_eph suggest that Mo3Sb7 belongs to intermediate-coupling regime. The
electronic band structure calculations indicate that the density of states near
the Fermi level is formed mainly by the Mo-4d orbitals and there is no
overlapping between the Mo- 4d and Sb-sp orbitals.
