The structure and powder diffraction data of Hägg-carbide (χ-Fe5C2) have been redetermined and improved by X-ray diffraction. Experimental values of 2θ, corrected for systematic errors, relative peak intensities, lattice spacings, and the Miller indices of 27 observed reflections up to 100° 2θ are reported. The unit cell is monoclinic (space group C2/c, Z=4) with a=11.588 Å, b=4.579 Å, c=5.059 Å, and β=97.75°. The crystal structure has been refined by Rietveld analysis, resulting in Rwp=0.073.