Fluorite & Anti Fluorite Crystal Structure

"Structure OF ionic Solids,Nacl type Structure,CSCL type Structure,Fluorite and Antifluorite Structure, Zinc Blende type Structure,Diamond Structure,Schottky and Frenkel Defect"

Try to answer the following: (i) In Zinc Blende structure there is one Zn^(+2) ion per S^(2-) ion. But the radius ratio lies in the range of Tetrahedral void and there are two tetrahedral voids available per S^(2-) . Can you given the idea about the arrangement of the lattice. (ii) What is the striking difference between the Fluorite and the Anit-fluorite structures

There are four formula units in fluorite and antifluorite structure.

Which of the follwing statements is/are correct for both fluorite and antifluorite structures?