# Assuming that we have an accuracy of 0.

What is the difference between the experimentally measured ion-ion distances provided at the beginning of this assignment and the ones predicted in problem 1. Assuming that we have an accuracy of 0.04Å in the measurement, which molecule if predicted ion-ion distances are accurate or not accurate with respect to their experimental ion-ion distances

In the ionic compounds LiF, NaCl, KBr, and RbI, the measured cation-anion distances are 2.01 Å (Li-F), 2.82 Å (Na-Cl), 3.30 Å (K-Br), and 3.67 Å (Rb-I), respectively.

1. Predict the cation-anion distance of each ionic compound above using the values of ionic radii given in Figure 7.7 on page 257 in the textbook.

LiF

the ionic radius of cation Li+ = 0.90A

The ionic radius of anion F-=1.19A

=0.90A + 1.19A

=2.09A

NaCI

the ionic radius of cation Na + = 1.16A

The ionic radius of anion CI-=1.67A

=1.16A + 1.67A

=2.83A

KBr

the ionic radius of cation K+ = 1.52A

The ionic radius of anion Br-=1.82A

=1.52A + 1.82A

=3.34A

RbI

the ionic radius of cation Rb+ = 1.66A

The ionic radius of anion I-=2.06A

=1.66A + 2.06A

=3.72A