Une nouvelle structure ordonnee derivee de la fluorine : Pb3ZrF10

Pb₃ZrF₁₀ crystallizes with orthorhombic symmetry, space group : Cmcm and unit-cell parameters : $\text{a}\text{= 10,713(3)}\text{A}\text{?}$, $\text{b}\text{= 12,817(4)}\text{A}\text{?}$, $\text{c}\text{= 5,909(2)}\text{A}\text{?}$ (Z = 4). Its structure has been solved and refined to a conventional R = 0,041 for 350 independent reflexions. It can be described as an ordered intergrowth of (Pb₂F₄)_n fluorite like monodimensional units and (Pb₄Zr₂F₁₆)_n columnar clusters built of two isolated square antiprisms sharing faces with four PbF₁₁] complex polyhedra.A structural mechanism based on the transformation of edgesharing fluorite cubes to isolated square antiprisms is proposed to explain the change from fluorite to the anion-excess fluorite like Pb₃ZrF₁₀ structure.Analogies with homologous structures are discussed.