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2.3 Basic structure types


                 CaF -type
                           2






                    Crystal data

                    Formula sum                                CaF    2
                    Crystal system                             cubic

                    Space group                                F m -3 m (no. 225)

                    Unit cell dimensions                       a = 5.4375(1) Å
                    Z                                          4




                    Atomic coordinates                                                                                    Coordination Ca



                    Atom          Ox.           Wyck.          x             y              z

                    Ca1           +2            4a             0             0              0
                    F1            -1            8c             1/4           1/4            1/4






                  Structural features:tructural features:
                  S
                  • all TH of CCP filled

                  • F is coordinated by 4 Ca (tetrahedron)

                  • Ca is coordinated by 8 F (cube)
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