the structure of the mineral fluorite is แคลเซียมฟลูออไร is based on an fcc unit cell of larger แคลเซียมไอออน in which all 8 tetrahedral holes are filled by smaller ฟลูออรีนไอออน.Because there is a total of 4 แคลเซียมไอออน in each unit cell, this arrangement satisfies the 1:2 mole ratio of แคลเซียมไอออน to ฟลูออไรไอออน.This structure is so common that it too has its own name: the fluorite structure.Other compounds having this structure include..............สารประกอบ...... Another group of compounds with a cation-to-anion mole ratio of 2:1 has an antifluorite structure.In the crystal lattices of these compounds, which include.......สาร......., the smaller cations occupy the tetrehedral holes formed by cubic closest packing of the larger anions.