The crystal structures of CeO 1.68 (C+Ce 2 O 3؉ ), Ce 7 O 12 , and Ce 11 O 20 with ordered oxygen vacancy distributions have been determined by re5nement of single crystal neutron di4raction data collected at ambient temperature. CeO 1.68 is cubic, of space group Ia3 with a ؍ 11.111(2) A s ; one of the two oxygen positions is partially occupied with a probability of 37(3)%. For Ce 7 O 12 the rhombohedral space group R3 with a ؍ 6.785(1) A s , ؍ 99.42(1)3 was con5rmed. Ce 11 O 20 is isomorphous to Tb 11 O 20 with the triclinic space group P1 . The lattice parameters are a ؍ 6.757(3) A s , b ؍ 10.260(5) A s , c ؍ 6.732(3) A s , ؍ 90.04(4)3, ؍ 99.80(4)3, and ؍ 96.22(4)3. For Ce 11 O 20 there are no 1 2 [1, 1, 1] F oxygen vacancy pairs, i.e., pairs corresponding to half of the space diagonal of the 6uorite lattice along [1, 1, 1] F . The shortest vacancy pair type in that structure is 1 2 [1, 1, 1] F , which is also present in the two other phases. High temperature neutron diffraction measurements showed that Ce 7 O 12 is stable up to 1072 K. Then it transforms into a 6uorite type structure with disordered oxygen vacancies.