  NaPrTe2, NaNdTe2, and NaTbTe2 are found to be triangular lattice magnets with
the alpha-NaFeO2 structure, where lanthanoid atoms with 4f electrons form a
triangular lattice, based on the structural analysis and physical property
measurements of synthesized polycrystalline samples. The alpha-NaFeO2 structure
is a new polymorph of NaPrTe2, which has been reported to crystallize in the
cubic LiTiO2 structure. Polytypism in NaPrTe2 was discussed based on the
structural parameters determined by the Rietveld analysis. NaPrTe2 is suggested
to be in the proximity of the phase boundary between the LiTiO2 and
alpha-NaFeO2 types, as compared to NaNdTe2 and NaTbTe2, indicating that this
compound might be interesting from the perspectives of the dimensional control
of geometrically frustrated lattices. The magnetic susceptibility and heat
capacity data indicated that NaPrTe2 do not show long-range magnetic order or a
spin-glass transition above 2 K.
