## Chemistry: The Central Science (13th Edition)

$r_{A}=\frac{d_{1}}{2}$. $r_X=d_2-\frac{d_1}{2}$
The distance of a bond between 2 atoms is the sum of the atomic radii of the 2 atoms. The atomic radii of A is is therefore $\frac{d_{1}}{2}$. The distance of the bond between A and X, $d_2$, is the sum of the atomic radii of A and X. $d_2=r_A+r_X$ $d_2=\frac{d_1}{2}+r_X$ $r_X=d_2-\frac{d_1}{2}$