Superconducting compounds of Y1B2C3−xFexOy, with x=0.125, 0.0625, 0.125 and 0.300, were studied using X-ray powder diffractometry. Two sets of samples were prepared. Samples quenched from 950°C to liquid nitrogen temperature showed a tetragonal non-superconducting phase, whose lattice parameters depend on the Fe content and differ from those of the yttrium 1:2:3 tetragonal phase. Samples oxygenated at 450°C showed an orthorhombic to tetragonal phase transition for Fe contents higher than x=0.0625. The lattice parameters of this tetragonal phase were different from those of both tetragonal phases mentioned above. All these observations allow us to conclude that C(l) sites are occupied at least partially by Fe impurities.