Type of isomerism exhibited by compounds $\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6]{\mathrm{Cl}}_3,\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_5\mathrm{Cl}]{\mathrm{Cl}}_2·{\mathrm{H}}_2\mathrm{O}\right.,\right.$$\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_4{\mathrm{Cl}}_2\right]\mathrm{Cl}.2{\mathrm{H}}_2\mathrm{O}$ and the value of coordination number (CN) of central metal ion in all these compounds, respectively is :