The diphosphate NaCeP 2 O 7 was synthesized and its structure was determined from single crystal X-ray data. The title compound crystallizes in the orthorhombic space group Pnma with: a=8.6224(4), b=5.2823(3), c=12.6796(6) Å, V=577.51(5) Å 3 , Z=4 and R(F 2 )=0.0323 for 674 reflections (F o 2 ≥2σ(F o 2 )) with R w (F 2 )=0.0775, refined with 62 parameters. The structure of NaCeP 2 O 7 consists of P 2 O 7 4− diphosphate groups which are extended along two perpendicular directions. In the case of the orthorhombic NaCeP 2 O 7 , cerium cations are ninefold coordinated and diphosphate groups have a symmetry plane. The sodium cations are coordinated by nine oxygen atoms and build ribbons of NaO 9 polyhedra running parallel to the b direction.The conductivity of the NaCeP 2 O 7 sample was studied over a temperature range from 293 to 840 K. Transport properties in this material appear to be due to Na + ions' hopping mechanism.