  Results are reported for single crystal specimens of Hf$_2$Te$_2$P and
compared to its structural analogue Zr$_2$Te$_2$P, which was recently proposed
to be a potential reservoir for Dirac physics.[1] Both materials are produced
using the iodine vapor transport method and the resulting crystals are
exfoliable. The bulk electrical transport and thermodynamic properties indicate
Fermi liquid behavior at low temperature for both compounds. Quantum
oscillations are observed in magnetization measurements for fields applied
parallel but not perpendicular to the $c$-axis, suggesting that the Fermi
surfaces are quasi-two dimensional. Frequencies are determined from quantum
oscillations for several parts of the Fermi surfaces. Lifshitz-Kosevich fits to
the temperature dependent amplitudes of the oscillations reveal small effective
masses, with a particularly small value $m^*$ $=$ 0.046$m_0$ for the {\alpha}
branch of Zr$_2$Te$_2$P. Electronic structure calculations are in good
agreement with quantum oscillation results and illustrate the effect of a
stronger spin-orbit interaction going from Zr to Hf. These results suggest that
by using appropriate tuning parameters this class of materials may deepen the
pool of novel Dirac phenomena.
