  In this work, we report the results of \emph{ab initio} calculations of
thermochemical properties of several compounds in the Fe-Nd, B-Nd and B-Fe-Nd
systems. We have performed DFT+U calculations to compute the enthalpy of
formation of the compounds NdB$_6$, NdB$_4$, Nd$_2$B$_5$, Nd$_2$Fe$_{17}$ and
Nd$_5$Fe$_2$B$_6$. It was found that the values obtained with an effective
Hubbard $U$ correction have better agreement with the experimental data. We
have also computed the vibrational contribution to the heat capacity ($C_p$) of
the compounds as a function of temperature was computed using the quasharmonic
approximation. For most of the compounds these properties have not been
experimentally determined until now. Hence, the computed \emph{ab initio}
thermodynamic properties will serve as useful input for the Gibbs energy model
parameter assessment using the CALPHAD method.
