The oxidation number coordination number and magnetic moment for the complex are ${\left[\mathrm{Cr}{\left({\mathrm{C}}_2{\mathrm{O}}_4\right)}_2{\left({\mathrm{NH}}_3\right)}_2\right]}^{-}$ respectively.

$\text{ O.N. }=+3,\text{ C.N. }=6,\text{ M.M. }=\sqrt{15}\text{ B.M. }$

$\text{ O.N. }=+1,\text{ C. }\mathrm{N}.=6,\mathrm{M}.\mathrm{M}.=\sqrt{15}\text{ B.M. }$

$\text{ O.N. }=+3,\text{ C. }\mathrm{N}.=6,\text{ M.M. }=\sqrt{3}\text{ B.M. }$

$\text{ O.N. }=+3,\text{ C.N. }=6,\text{ M.M. }=\sqrt{24}\text{ B.M. }$