Consider the Three Unit Cells Below for Ionic Solids

Short Answer

Consider the three unit cells below for ionic solids. In each unit cell, one of the ions is arranged in one of the standard unit cell structures while the other is found between these sites. What are the names of the minerals associated with each of these structures? I ________; II ________;
III ________.
$\begin{array} { c c c } \text { I } & \text { II } & \text { III } \\ \text { In addition to the ions } & \text { There are } 14 \text { large and } & \text { There are } 14 \text { small and } \\ \text { shown, there is another } & 4 \text { small ions depicted. } & 8 \text { large ions depicted. } \\ \text {at the very center of the }\\ \text {unit cell. }\\\end{array}$