18.53 For CaO, the ionic radii for Ca2 and O2 ions are 0.100 and 0.140 nm, respectively. If an externally applied electric field produces a 5% expansion of the lattice, compute the dipole moment for each Ca2O2pair. Assume that this material is completely unpolarized in the absence of an electric field.

Explanation:

Given:

Let's find the distance of separation between cation and anion when there is no applied electric field with the formula:

d = 0.100 nm + 0.140 nm

= 0.240 nm

Let's also calculate the distance of separation between anion and cation when there is an applied electric field.

We use the formula:

∆d = 5%d => 0.05d

= 0.05 * 0.024 nm

∆d = 0.0120 nm

Given magnitude of each dipole=

Let's find the dipole moment, with the formula:

p = q∆d

Substituting figures in the formula, we have:

answer: i would say b.

explanation: