Chapter 19, Problem 24E

(a)

Interpretation Introduction

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

• ${\text{[Cr(H}}_{\text{2}}{\text{O)}}_5{\text{Br]Br}}_{\text{2}}$

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 24E

  ${\text{[Cr(H}}_{\text{2}}{\text{O)}}_5{\text{Br]Br}}_{\text{2}}$ = pentaaquabromochromium(III) bromide

Explanation of Solution

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

• The name of ligand will come with prefix of number of ligands.
• Name of metal will come with oxidation number in Roman numeral.
• Name of cation will come first followed by name of anion.
• The ligands are named before the metal ion in sequence of neutral, negative, positive.
• The name of anionic ligand must be ended in -ido.
• The name of complex ion with negative charge must be end in −ate.

In ${\text{[Cr(H}}_{\text{2}}{\text{O)}}_5{\text{Br]Br}}_{\text{2}}$ , there are two Br-present as counter ion so the complex ion must have +2 charge. In the complex ion, there are 5H₂O ligands so penta- prefix must be used with −aqua and one bromo ligand. Since −aqua ligand is neutral therefore there will be +3 charge on metal to balance the charge on complex as +2. Hence name of ${\text{[Cr(H}}_{\text{2}}{\text{O)}}_5{\text{Br]Br}}_{\text{2}}$ must be pentaaquabromochromium(III) bromide.

(b)

Interpretation Introduction

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

• ${\text{Na}}_{\text{3}}{\text{[Co(CN)}}_6\text{]}$

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 24E

  ${\text{Na}}_{\text{3}}{\text{[Co(CN)}}_6\text{]}$ = sodium hexacyanocobaltate(III)

Explanation of Solution

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

• The name of ligand will come with prefix of number of ligands.
• Name of metal will come with oxidation number in Roman numeral.
• Name of cation will come first followed by name of anion.
• The ligands are named before the metal ion in sequence of neutral, negative, positive.
• The name of anionic ligand must be ended in -ido.
• The name of complex ion with negative charge must be end in −ate.

In ${\text{Na}}_{\text{3}}{\text{[Co(CN)}}_6\text{]}$ , there are3Na+ present as counter ion so the complex ion must have -3 charge. In the complex ion there are 6CN- ligands so hexa- prefix must be used with −cyano. The -6 charge of ligand and -3 charge on complex shows that Co must have +3 charge. Hence name of ${\text{[Cr(H}}_{\text{2}}{\text{O)}}_5{\text{Br]Br}}_{\text{2}}$ must be sodium hexacyanocobaltate(III).

(c)

Interpretation Introduction

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

• ${\text{[Fe(NH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}{\text{)}}_{\text{2}}{{\text{(NO}}_{\text{2}}\text{)}}_{\text{2}}\text{]Cl}$

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 24E

  ${\text{[Fe(NH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}{\text{)}}_{\text{2}}{{\text{(NO}}_{\text{2}}\text{)}}_{\text{2}}\text{]Cl}$ = bis (ethylenediammine) dinitroiron(III) chloride.

Explanation of Solution

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

• The name of ligand will come with prefix of number of ligands.
• Name of metal will come with oxidation number in Roman numeral.
• Name of cation will come first followed by name of anion.
• The ligands are named before the metal ion in sequence of neutral, negative, positive.
• The name of anionic ligand must be ended in -ido.
• The name of complex ion with negative charge must be end in −ate.

In ${\text{[Fe(NH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}{\text{)}}_{\text{2}}{{\text{(NO}}_{\text{2}}\text{)}}_{\text{2}}\text{]Cl}$ , there are1Cl- present as counter ion so the complex ion must have +1 charge. In the complex ion there are 2 ${\text{NH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}$ ligands so bis- prefix must be used with −ethylenediammine. Another ligand - ${\text{NO}}_{\text{2}}$ has -1 charge hence the metal ion must have +3 charge.

Hence name of ${\text{[Fe(NH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{NH}}_{\text{2}}{\text{)}}_{\text{2}}{{\text{(NO}}_{\text{2}}\text{)}}_{\text{2}}\text{]Cl}$ must be bis (ethylenediammine) dinitroiron(III) chloride.

(d)

Interpretation Introduction

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

• ${\text{[Pt(NH}}_{\text{3}}{\text{)}}_{\text{4}}{\text{I}}_{\text{2}}{\text{][PtI}}_{\text{4}}\text{]}$

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 24E

  ${\text{[Pt(NH}}_{\text{3}}{\text{)}}_{\text{4}}{\text{I}}_{\text{2}}{\text{][PtI}}_{\text{4}}\text{]}$ = tetraamminediiodoplatinum(IV) tetraiodoplatinate(II).

Explanation of Solution

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

• The name of ligand will come with prefix of number of ligands.
• Name of metal will come with oxidation number in Roman numeral.
• Name of cation will come first followed by name of anion.
• The ligands are named before the metal ion in sequence of neutral, negative, positive.
• The name of anionic ligand must be ended in -ido.
• The name of complex ion with negative charge must be end in −ate.

In ${\text{[Pt(NH}}_{\text{3}}{\text{)}}_{\text{4}}{\text{I}}_{\text{2}}{\text{][PtI}}_{\text{4}}\text{]}$ , both cation and anion are complex ion. In cation there are ammine and iodo ligands with Pt as metal ion with +4 oxidation state. Thus, the charge of the cation will be +2

Now, for overall charge to be neutral, the charge of the anionic part should be -2. For that, the oxidation state of Pt in ${\text{[PtI}}_{\text{4}}\text{]}$ will be:

  $\begin{array}{l}x+4\left(-1\right)=-2\\ x=-2+4=+2\end{array}$

Hence name of ${\text{[Pt(NH}}_{\text{3}}{\text{)}}_{\text{4}}{\text{I}}_{\text{2}}{\text{][PtI}}_{\text{4}}\text{]}$ must be tetraamminediiodoplatinum(IV) tetraiodoplatinate(II).