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We report on single crystal growth, single crystal x-ray diffraction, physical properties and density functional theory (DFT) electronic structure as well as Fermi surface calculations for two ternary carbides, LuCoC2 and LuNiC2. Electrical resistivity measurements reveal for LuNiC2 a charge density wave (CDW) transition at TCDW 450 K and, for T > TCDW, a significant anisotropy of the electrical resistivity, which is lowest along the orthorhombic a-axis. The analysis of x-ray superstructure reflections suggest a commensurate CDW state with a Peierls-type distortion of the Ni atom periodicity along the orthorhombic a-axis. DFT calculations based on the CDW modulated monoclinic structure model of LuNiC2 as compared to results of the orthorhombic parent-type reveal the formation of a partial CDW gap at the Fermi level which reduces the electronic density of states from N (EF) = 1.03 states/eV f.u. without CDW to N (EF) = 0.46 states/eV f.u. in the CDW state. The corresponding bare DFT Sommerfeld value of the latter, γ CDW DFT = 0.90 mJ/mol K 2 , reaches reasonable agreement with the experimental value γ = 0.83(5) mJ/mol K 2 of LuNiC2. LuCoC2 displays a simple metallic behavior with neither CDW ordering nor superconductivity above 0.4 K. Its experimental Sommerfeld coefficient, γ = 5.9(1) mJ/mol K 2 , is in realistic correspondence with the calculated, bare Sommerfeld coefficient, γDFT = 3.82 mJ/mol K 2 , of orthorhombic LuCoC2.

The results of experimental investigations of the temperature dependences of the surface resistance and specific heat of ternary rare-earth compounds are presented: LuFe4Al8, ScFe4Al8, CeFe4Al8, CeCr4Al8, YFe4Al8, YCr4Al8, YMn4Al8, UCu4Al8, LaAg6In6, and PrAg6In6, which have ThMn12 structure. It is shown that at a certain temperature, characteristic for each compound with Fe, Cr, and Mn, below the Néel temperature a jump is observed in the total impedance and specific heat. At lower temperatures a negative magnetoresistance is observed in these compounds in weak magnetic fields. Superconducting phases are found in the compounds ScFe4Al8 (Tc=6 K), YCr4Al8 (Tc=4.5 K), YFe4Al8 (Tc=6 K), and PrAg6In6 (Tc=8.3 K).

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