Question

What is the formula of ammonium aquapentafluoronickelate(IV)?

• A. $\left[Ni\right(N{H}_3\left)\right(H_{2}O)F_5{]}^{+1}$
• B. $\left[Ni\right(N{H}_3\left)\right(H_{2}O\left)F_5\right]$
• C. $\left(N{H}_4{)}_2\right[Ni\left(H_{2}O\right)F_5]$
• D. $N{H}_4\left[Ni\right(H_{2}O\left)F_5\right]$

Answer 1

The correct option is D $N{H}_4\left[Ni\right(H_{2}O\left)F_5\right]$

Option (C) is correct. Formula of ammonium aquapentafluoronickelate(IV) is $N{H}_4\left[Ni\right(H_{2}O\left)F_5\right]$.

In this complex, $N{H}_4$ will come first and carries +1 charge. $H_{2}O$(aqua) is a neutral ligand and $F$ has -1 charge. The oxidation state of nickel in this complex will be -3 so the word 'ate' has been used. Oxidation state is written in roman letters within the brackets.