The single crystals of a new quaternary compound ErRh2B2C have been obtained as thin plates in an atmosphere of helium by the flux method using molten copper. The single crystals show golden-colored luster and the maximum size obtained is about 1.0×1.0×0.02mm3. This compound belongs to a tetragonal system and seems to be a derivative of ThCr2Si2 type; lattice parameter: a=0.36848(2)nm, c=1.05520(3)nm, V=1.4327×10-28m3 and Z=2. The electrical resistivity parallel to the a-b plane decreases monotonically with decreasing temperature, but no superconductivity is observed down to 1.5K. The residual resistivity ratio, ρ(273K)/ρ(1.5K), is 1.38. Similar type new compounds of RRh2B2C were obtained for R=La-Er (except Eu and Tm) and Y by arc-melting synthetic method.
