Question

Write the formula for the phosphate salt (if the complex ion is a cation) or the aluminum salt (if the complex ion is an anion) for the following ions.

[Mo(CN)₂(en)₂]⁺

[Co(H₂O)(OH)₂Cl]^-

Answer 1

[Mo(CN)2(en)2]+

1. Identify the central metal ion: Molybdenum, Mo
2. Identify the charge on the central metal ion (shown in parantheses): +
3. Identify the ligands: Cyano = CN(Monoanionic)

        Ethylenediamine = en(Neutral)

1. Identify the number of ligands: tetra = 4
2. Calculate the total charge on the ligands = (-2 x 1) + (0 x 2) = -2
3. Calculate the charge on the complex ion = charge on metal ion + total charge on ligands = 1+ - 2 = -1

As the charge shows it is anionic complex. It will be written with aluminum salt.

Aluminum is 3+, it will bind three of these complexes as it has -1 or single complex with Al2+ depending on pH. (step f).

Al.[Mo(CN)2(en)2]3

[Co(H2O)(OH)2Cl]-

1. Identify the central metal ion: Cobalt, Co
2. Identify the charge on the central metal ion (shown in parantheses): -
3. Identify the ligands: Water = H2O(Neutral)

        Hydroxide = OH(Monoanionic)

        Chloride = Cl(Monoanionic)

1. Identify the number of ligands: tetra = 4
2. Calculate the total charge on the ligands = -3
3. Calculate the charge on the complex ion = charge on metal ion + total charge on ligands = -1+ - 3 = -4

As the charge shows it is anionic complex. It will be written with aluminum salt.

Al3+[Co(H2O)(OH)2Cl]-