X-ray diffraction methods were used to determine the cell constants and structure of CeNi. The unit cell is orthohombic. The spcae group is probably Cmcm with aO=3.77 +/- 0.01, bO=10.46 +/- 0.02, cO=4.37+/- 0.01 A. The cell formula is Ce4Ni4. The observed density if 7.51 grams/cm3 and the calculated density is 7.65 grams/cm3, a deviation of 1.8%
