  We report heat capacity measurements of the pnictide materials
SmFeAsO$_{1-x}$F$_x$, NdFeAsO, LaFeAsO$_{1-x}$F$_x$ and LiFeAs. For
SmFeAsO$_{1-x}$F$_x$, with x close to 0.1, we use 3 He measurements to
demonstrate a transfer of entropy from the peak at TN to a previously
unidentified ~2 K feature which grows with increasing doping. Our results on
the Sm samples are compared with a similarly doped La sample to elucidate the
crystal field levels of the Sm3+ ion at 0, 23, and 56 meV which lead to a
Schottky-like anomaly, and also show that there is a significant increase in
the Sommerfeld coefficient $\gamma$ when La is replaced by Sm or Nd. The
lattice contribution to the heat capacity of the superconducting oxypnictides
is found to vary negligibly with chemical substitution. We also present a heat
capacity measurement of LiFeAs showing the feature at Tc, which is
significantly rounded and much smaller than the BCS value.
