Chapter 19, Problem 22QAP

Interpretation Introduction

(a)

Interpretation:

The name of the complex $\left[\text{Fe}{\left({\text{H}}_{\text{2}}\text{O}\right)}_6^{3+}\right]$ needs to be determined.

Concept introduction:

Coordination compounds are those in which a transition metal atom is bonded to a ligand which can be neutral cation or anion. The transition metal element is enclosed within a bracket and a charge is present on the ion to balance the charge present on the ligands. The total charge present on any complex ion is equal to the sum of the oxidation number of the central metal atom and the total charge on the ligand present in it.

Answer to Problem 22QAP

The name of this complex cation will be hexaaquairon(III).

Explanation of Solution

A ligand is an atom or a group of atoms or an anion that has an unshared pair of electrons and thus it can act as a Lewis base. It can donate its pair of electrons to the metal atom to form a coordinate bond with the transition metal atom. The formula of the given compound is

$\left[\text{Fe}{\left({\text{H}}_{\text{2}}\text{O}\right)}_6^{3+}\right]$

The total charge on complex cation is +3. Let ‘x’ be the oxidation state of ‘Fe’ in the complex cation.

$\begin{array}{l}+3=x+6\left(0\right)\hfill \\ -1=x+0\hfill \\ x=+3\hfill \end{array}$

This complex cation consists of only water molecules as ligands. Water molecules are written as ‘aqua’ while naming in coordination compounds. Since it consists of six water ligands, therefore the number of ligands in a given coordination compound is given by Greek prefix −‘hexa’.The naming of the cation is done as such, therefore the name of the compound will be hexaaquairon(III).

Interpretation Introduction

(b)

Interpretation:

The name of the complex $\left[\text{Pt}{\left(\text{NH}\right)}_{\text{3}}{\text{Br}}_3^{-}\right]$ needs to be determined.

Concept introduction:

Coordination compounds are those in which a transition metal atom is bonded to a ligand which can be neutral cation or anion. The transition metal element is enclosed within a bracket and a charge is present on the ion to balance the charge present on the ligands. The total charge present on any complex ion is equal to the sum of the oxidation number of the central metal atom and the total charge on the ligand present in it.

Answer to Problem 22QAP

The name of this complex anion is amminetribromoplatinate(II).

Explanation of Solution

A ligand is an atom or a group of atoms or an anion that has an unshared pair of electrons and thus it can act as a Lewis base. It can donate its pair of electrons to the metal atom to form a coordinate bond with the transition metal atom. The formula of the given compound is

‘ $\left[\text{Pt}{\left(\text{NH}\right)}_{\text{3}}{\text{Br}}_3^{-}\right]$

For naming this compound, we can see that it consists of threebromine ligands. It is an anionic ligand as it carries a charge of -1 and the number of such anionic ligands is denoted by adding prefix such as -di, -tri depending upon the number of the ligands. It also consists of one ammonia molecule which is a neutral ligand and is denoted by ‘ammine’. Naming of the ligands in a given coordination compound takes place in an alphabetical order. For naming complex ions, the oxidation state of the central metal atom is written at the end of the name in roman numerals in round brackets. Since the given compound is a complex anion, therefore while naming the central metal atom, a suffix -ate is added to the name of the central metal atom. The total charge on the complex cation is -1. Let ‘x’ be the oxidation state of ‘Pt’.

$\begin{array}{l}-1=x+1\left(0\right)+3\left(-1\right)\hfill \\ -1=x-3\hfill \\ x=-1+3\hfill \\ x=+2\hfill \end{array}$

The name of the coordination compound will be amminetribromoplatinate(II).

Interpretation Introduction

(c)

Interpretation:

The name of the complex $\left[\text{V}\left(\text{en}\right){\text{Cl}}_4^{2-}\right]$ needs to be determined.

Concept introduction:

Coordination compounds are those in which a transition metal atom is bonded to a ligand which can be neutral cation or anion. The transition metal element is enclosed within a bracket and a charge is present on the ion to balance the charge present on the ligands. The total charge present on any complex ion is equal to the sum of the oxidation number of the central metal atom and the total charge on the ligand present in it.

Answer to Problem 22QAP

The name of this complex anion is tetrachloro(ethylenediamine)vanadate(II).

Explanation of Solution

A ligand is an atom or a group of atoms or an anion that has an unshared pair of electrons and thus it can act as a Lewis base. It can donate its pair of electrons to the metal atom to form a coordinate bond with the transition metal atom. The formula of the given compound is

$\left[\text{V}\left(\text{en}\right){\text{Cl}}_4^{2-}\right]$.

For naming this compound, we can see that it consists of one ethylenediamine ligand. It is a neutral ligand and is denoted by ‘en’. Chloride ion is also an anionic ligand and is written as ‘chloro’ while naming coordination compounds and the oxidation state of the central metal atom is written at the end of the name in roman numerals in round brackets. Since the given compound is a complex anion therefore while naming the central metal atom, a suffix -ate is added to the name of the central metal atom. The total charge on the complex anion is -2. Let ‘x’ be the oxidation state of ‘V’.

$\begin{array}{l}-2=x+1\left(0\right)+4\left(-1\right)\hfill \\ -2=x-4\hfill \\ x=-2+4\hfill \\ x=+2\hfill \end{array}$

The name of the coordination compound will be tetrachloro(ethylenediamine)vanadate(II).

Interpretation Introduction

(d)

Interpretation:

The name of the complex $\left[\text{Au}{\left(\text{CN}\right)}_2^{+}\right]$ needs to be determined.

Concept introduction:

Coordination compounds are those in which a transition metal atom is bonded to a ligand which can be neutral cation or anion. The transition metal element is enclosed within a bracket and a charge is present on the ion to balance the charge present on the ligands. The total charge present on any complex ion is equal to the sum of the oxidation number of the central metal atom and the total charge on the ligand present in it.

Answer to Problem 22QAP

The name of this complex cation will be dicyanogold(III).

Explanation of Solution

A ligand is an atom or a group of atoms or an anion that has an unshared pair of electrons and thus it can act as a Lewis base. It can donate its pair of electrons to the metal atom to form a coordinate bond with the transition metal atom. The formula of the given compound is $\left[\text{Au}{\left(\text{CN}\right)}_2^{+}\right]$

For naming this compound, we can see that it consists of two cyanide ligands. It is an anionic ligand as it carries a charge of -1 and the number of such anionic ligands is denoted by adding prefix such as -di, -tri depending upon the number of the ligands. For naming complex ions, the oxidation state of the central metal atom is written at the end of the name in roman numerals in round brackets. Since the given compound is a complex cation therefore it will be named as such. The total charge on the complex cation is +1. Let ‘x’ be the oxidation state of ‘Au’.

$\begin{array}{l}+1=x+2\left(-1\right)\hfill \\ +1=x-2\hfill \\ x=+1+2\hfill \\ x=+3\hfill \end{array}$

The name of the coordination compound will be dicyanogold(III).