Question

The coordination number and oxidation state of $Cr$ in $K_3\left[Cr\right(C_2{O}_4{)}_3]$ are respectively__________.

• A. $3$ and $+3$
• B. $2$ and $0$
• C. $6$ and $+3$
• D. $4$ and $+2$

Answer 1

Answer: (C)

$6$ and $+3$

$C_2{O}_4^{2-}$ is bidentate ligand so coordination number is $3\left(2\right)=6$

Oxidation number of $K=+1$

Oxidation number of $C_2{O}_4=-2$

Let oxidation number of $Cr$ is $=x$

$3(+1)+x+3(-2)=0$

$x=+3$.