Chapter 19, Problem 73AE

(a)

Interpretation Introduction

Interpretation: The formula for the given coordination complex needs to be determined.

• Hexakis(pyridine)cobalt(III) chloride

Concept Introduction: A coordination complex is composed of two main parts; metal atom/ ion and ligand. Ligands are the atom/ group of atom/ ion that can donate its extra pair of electrons to the electron deficient metal cation. It leads to the formation of coordinate bond between metal ion and ligand.

Answer to Problem 73AE

  ${\text{[Co(C}}_{\text{5}}{\text{H}}_{\text{5}}{\text{N)}}_{\text{6}}{\text{]Cl}}_{\text{3}}$

Explanation of Solution

In the formula of writing and naming of coordination complex; IUPAC rule must be followed.

• Atomic symbol of the metal center must be written first in the square bracket.
• Ligands must be written after metal symbol in sequence of anion then neutral ligand.
• The ligands must be written in alphabetical order.
• The number of ligands or metal must be indicated as sub-script.
• Counter ion must be written outside the square bracket.

In Hexakis(pyridine)cobalt(III) chloride; chloride ion is counter ion with ${\mathrm{Co}}^{3+}$ as metal ion and 6py as ligands. Since pyridine is a neutral ligand therefore the charge on the complex ion must be +3 that must be balanced by three chloride ion. Hence the formula must be ${\text{[Co(C}}_{\text{5}}{\text{H}}_{\text{5}}{\text{N)}}_{\text{6}}{\text{]Cl}}_{\text{3}}$ .

(b)

Interpretation Introduction

Interpretation: The formula for the given coordination complex needs to be determined.

• Pentaammineiodochromium(III) iodide

Concept Introduction: A coordination complex is composed of two main parts; metal atom/ ion and ligand. Ligands are the atom/ group of atom/ ion that can donate its extra pair of electrons to the electron deficient metal cation. It leads to the formation of coordinate bond between metal ion and ligand.

Answer to Problem 73AE

  ${\text{[Cr(NH}}_{\text{3}}{\text{)}}_{\text{5}}{\text{I]I}}_{\text{2}}$

Explanation of Solution

In the formula of writing and naming of coordination complex; IUPAC rule must be followed.

• Atomic symbol of the metal center must be written first in the square bracket.
• Ligands must be written after metal symbol in sequence of anion then neutral ligand.
• The ligands must be written in alphabetical order.
• The number of ligands or metal must be indicated as sub-script.
• Counter ion must be written outside the square bracket.

In Pentaammineiodochromium(III) iodide; iodide ion is counter ion with ${\text{Cr}}^{\text{3+}}$ as metal ion and 5 ${\text{NH}}_{\text{3}}$ , 1 iodo as ligands. Since ${\text{NH}}_{\text{3}}$ is a neutral ligand therefore the charge on the complex ion must be +2 that must be balanced by 2iodide ion. Hence the formula must be ${\text{[Cr(NH}}_{\text{3}}{\text{)}}_{\text{5}}{\text{I]I}}_{\text{2}}$ .

(c)

Interpretation Introduction

Interpretation: The formula for the given coordination complex needs to be determined.

• Tris(ethylenediamine)nickel(II) bromide

Concept Introduction: A coordination complex is composed of two main parts; metal atom/ ion and ligand. Ligands are the atom/ group of atom/ ion that can donate its extra pair of electrons to the electron deficient metal cation. It leads to the formation of coordinate bond between metal ion and ligand.

Answer to Problem 73AE

  ${\text{[Ni(NH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}{\text{)}}_{\text{3}}{\text{]Br}}_{\text{2}}$

Explanation of Solution

In the formula of writing and naming of coordination complex; IUPAC rule must be followed.

• Atomic symbol of the metal center must be written first in the square bracket.
• Ligands must be written after metal symbol in sequence of anion then neutral ligand.
• The ligands must be written in alphabetical order.
• The number of ligands or metal must be indicated as sub-script.
• Counter ion must be written outside the square bracket.

In Tris(ethylenediamine)nickel(II) bromide; bromide ion is counter ion with ${\text{Ni}}^{\text{2+}}$ as metal ion and 3 ${\text{NH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}$ as ligands. Since ${\text{NH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}$ is a neutral ligand therefore the charge on the complex ion must be +2 that must be balanced by 2 bromide ion. Hence the formula must be ${\text{[Ni(NH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}{\text{)}}_{\text{3}}{\text{]Br}}_{\text{2}}$ .

(d)

Interpretation Introduction

Interpretation: The formula for the given coordination complex needs to be determined.

• Potassium tetracyanonickelate(II)

Concept Introduction: A coordination complex is composed of two main parts; metal atom/ ion and ligand. Ligands are the atom/ group of atom/ ion that can donate its extra pair of electrons to the electron deficient metal cation. It leads to the formation of coordinate bond between metal ion and ligand.

Answer to Problem 73AE

  ${\text{[Ni(NH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}{\text{)}}_{\text{3}}{\text{]Br}}_{\text{2}}$

Explanation of Solution

In the formula of writing and naming of coordination complex; IUPAC rule must be followed.

• Atomic symbol of the metal center must be written first in the square bracket.
• Ligands must be written after metal symbol in sequence of anion then neutral ligand.
• The ligands must be written in alphabetical order.
• The number of ligands or metal must be indicated as sub-script.
• Counter ion must be written outside the square bracket.

In Potassium tetracyanonickelate(II); potassium ion is counter ion with ${\text{Ni}}^{\text{2+}}$ as metal ion and 4 ${\text{CN}}^{\text{-}}$ as ligands. Since ${\text{CN}}^{\text{-}}$ is an anionic ligand therefore total charge by ligand is -4 which get balance with ${\text{Ni}}^{\text{2+}}$ and charge on complex ion will be -2. Hence the formula must be ${\text{[Ni(NH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}{\text{)}}_{\text{3}}{\text{]Br}}_{\text{2}}$ .

(e)

Interpretation Introduction

Interpretation: The formula for the given coordination complex needs to be determined.

• Tetraamminedichloroplatinum(IV) tetrachloroplatinate(II)

Concept Introduction: A coordination complex is composed of two main parts; metal atom/ ion and ligand. Ligands are the atom/ group of atom/ ion that can donate its extra pair of electrons to the electron deficient metal cation. It leads to the formation of coordinate bond between metal ion and ligand.

Answer to Problem 73AE

  ${\text{[Pt(NH}}_{\text{3}}{\text{)}}_{\text{4}}{\text{Cl}}_{\text{2}}{\text{][PtCl}}_{\text{4}}\text{]}$

Explanation of Solution

In the formula of writing and naming of coordination complex; IUPAC rule must be followed.

• Atomic symbol of the metal center must be written first in the square bracket.
• Ligands must be written after metal symbol in sequence of anion then neutral ligand.
• The ligands must be written in alphabetical order.
• The number of ligands or metal must be indicated as sub-script.
• Counter ion must be written outside the square bracket.

In Tetraamminedichloroplatinum(IV) tetrachloroplatinate(II); both cation and anion are complex ions. Cation Tetraamminedichloroplatinum(IV), has 4 ammine ligands, two chloro ligands with ${\text{Pt}}^{\text{4+}}$ as metal ion. Aniontetrachloroplatinate(II), has 4 chloro ligands with ${\text{Pt}}^{\text{4+}}$ as metal ion.

Hence the formula must be ${\text{[Pt(NH}}_{\text{3}}{\text{)}}_{\text{4}}{\text{Cl}}_{\text{2}}{\text{][PtCl}}_{\text{4}}\text{]}$ .