Question

The range of radius ratio (cationic to anionic) for an octahedral arrangement of ions in an ionic solid is:

• A. $0.155-0.225$
• B. $0.225-0.414$
• C. $0.414-0.732$
• D. $0.732-1.000$

Answer 1

The correct option is C $0.414-0.732$

Limiting radius ratio = r/R	Coordination Number of cation	Structural Arrangement (Geometry of voids)	Example
0.155-0.225 0.225-0.414 0.414-0.732 0.414-0.732 0.732-1.000	3 4 4 6 8	Plane Trigonal Tetrahedral Square planar Octahedral Cubic	Boron Oxide $ZnS,Si{O}_2$ - $NaCI,Mg{O}_2$ $CsCI$