Final answer:
To calculate the unit cell edge length of MgO, substitute the given radius value into the formula Edge length = 2 * radius of the ion.
Step-by-step explanation:
To calculate the unit cell edge length of MgO, we need to determine the radius of the Mg²⁺ ion. The edge length of the unit cell can be found using the formula:
Edge length = 2 * radius of the ion
Given that the radius of the Mn³⁺ ion is 0.65 Å, we can substitute this value into the formula to find the edge length of the unit cell of MgO.
Edge length = 2 * 0.65 Å = 1.3 Å