The crystal structure of kukharenkoite-(Ce), Ba₂REE(CO₃)₃F, from the Khibina carbonatite, Kola Peninsula, Russia, has been refined to R = 0.044 (wR = 0.112) using 2296 reflections. The mineral is monoclinic, space group P2₁/m, with a 13.374(3), b 5.1011(8), c 6.653(1) Å, ß 106.56(1)°, V 435.1(1) ų, Z = 2. The structure is similar to that determined by Mercier & Leblanc (1993) for synthetic Ba₂Ce(CO₃)₃F. The F^- anion is tetrahedrally coordinated by three Ba and one Ce cations. F-centered [FCeBa₃] tetrahedra are linked through shared edges to form double chains {uB, 2_∞¹}[FCeBa] along the b axis. C(3)O₃ carbonate groups are positioned on the faces of the [FCeBa₃] tetrahedra, resulting in complex [FCeBa](CO₃) chains. These chains are positioned in sheets parallel to (001) (layer A) and alternating along [001] with sheets formed by C(1)O₃ and C(2)O₃ groups and Ba atoms that do not bond with fluorine (layer B). The structures of other fluorocarbonates with fluorine-centered tetrahedra contain the following tetrahedral complexes: double chains {uB, 2_∞¹} [F₂M₅] in cebaite-(Ce), Ba₃Ce₂(CO₃)₅F₂, and Ba₃La₂(CO₃)₅F₂, layers {uB, 1_∞²}[F₂M₃] in huanghoite-(Ce), BaCe(CO₃)₂F, and BaSm(CO₃)₂F, layers {uB, 1_∞²}[FM] in kettnerite, CaBiOF(CO₃), frameworks {_∞³}[FM] in brenkite, Ca₂F₂(CO₃), and Pb₂F₂(CO₃), frameworks {_∞³}[FM] in BaCu(CO₃)F₂, and frameworks {_∞³}[FM₄] in horváthite-(Y), NaY(CO₃)F₂. Topologically similar structural units composed of [OM₄] tetrahedra have been described in oxysalts with "additional" oxygen atoms.