Calcium fluoride is the well-known mineral fluorite. Each unit cell contains four Ca²⁺ ions and eight F⁻ ions. The F⁻ ions fill all the tetrahedral holes in a face-centered cubic lattice of Ca²⁺ ions. The edge of the CaF₂ unit cell is 5.46295 × 10⁻⁸ cm in length. The density of the solid is 3.1805 g/cm³. Use this information to calculate Avogadro’s number.