Chapter 7 - Periodic Properties of the Elements - Additional Exercises - Page 294: 7.89b

$Co^{4+} \lt Co^{3+}\lt Li^{+}$

$Co^{4+}$ has an atomic radiii of $0.67\dot{A}$. $Co^{3+}$ has an atomic radiii of $0.75\dot{A}$. $Li^{+}$ has an atomic radiii of $0.90\dot{A}$. $Co^{4+}$ is the smallest and $Li^{+}$ is the largest.