The ratio of spin-only magnetic moment value ${\mathrm{\mu }}_{\mathrm{eff}}{\left[\mathrm{Cr}{\left(\mathrm{CN}\right)}_6\right]}^{3-}/{\mathrm{\mu }}_{\mathrm{eff}}{\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}$ is __________.

In both ${\left[\mathrm{Cr}{\left(\mathrm{CN}\right)}_6\right]}^{3-}\&{\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}$complex ions the central metal atom chromium is in +3 oxidation state, and has valence configuration $3{\mathrm{d}}^{3}4{\mathrm{s}}^0$.
Under both strong and weak field cases the configuration of ${\mathrm{Cr}}^{+3}$ is ${\mathrm{t}}_{2\mathrm{g}}^3{\mathrm{e}}_{\mathrm{g}}^0$ with three unpaired electrons (n = 3).
Spin only magnetic moment ${\mathrm{\mu }}_{\mathrm{s}}=\sqrt{\mathrm{n}(\mathrm{n}+2)}=\sqrt{3(3+2)}=\sqrt{15}\mathrm{B}.\mathrm{M}$
$\therefore$The ratio is 1 : 1