The discovery of novel quaternary intermetallic compounds R2MoSi2C (R = Y, Gd) in the R-Mo-Si-C system is reported. Their crystal structure was investigated using single-crystal X-ray diffraction. It is shown that the Y2MoSi2C and Gd2MoSi2C compounds crystallize in the tetragonal space group P4/mbm (Pearson symbol tP12) with unit-cell parameters a = 6.9525 (18) Å, c = 4.1962 (16) Å, and a = 6.9945 (16) Å, c = 4.2020 (14) Å, respectively.
Keywords: X-ray diffraction; intermetallic compounds; quaternary carbides; single crystals.