Problem 81
Page 475
Section: Cumulative Problems
Chapter 11: Liquids, Solids, and Intermolecular Forces
Given information
Silver iodide crystallizes in the zinc blende structure. The separation between nearest neighbor cations and anions is approximately , and the melting point is .Cesium chloride, by contrast, crystallizes in the structure shown in Figure . Even though the separation between nearest neighbor cations and anions in cesium chloride is greater ( ), the melting point is still higher ( ). Explain why the melting point of cesium chloride is higher than that of silver iodide.
Step-by-step explanation
Silver iodide crystallizes in the zinc blende structure.
Where ions are the cations and ions are the anions.
The ions are anions and are face centered.Hence the coordination number is .Each anion is surrounded by four cations and the same for cations also.
Cesium chloride has body centred cubic structure.
The coordination number of the cubic cell is 8.Hence one anion is surrounded by or bound to cations and vice versa.