Chapter 9, Problem 9C.2E

(a)

Interpretation Introduction

Interpretation:

The name of the complex ${\left[\text{Cr}{\left(\text{Cl}\right)}_{\text{3}}{\left({\text{NH}}_{\text{3}}\right)}_{\text{2}}\left({\text{OH}}_{\text{2}}\right)\right]}^{\text{+}}$ has to be given.

Concept Introduction:

Rules for naming the complex:

• Name the ligands first, and then the metal atom or ion. A Roman numeral in parentheses denotes the oxidation number of the central metal ion.
• Neutral ligands, such as $\text{H2NCH2CH2NH2}$ (ethylenediamine) have the same name as the molecule, except for ${\text{H}}_{\text{2}}\text{O}$ (aqua), ${\text{NH}}_{\text{3}}$ (ammine), $\text{CO}$ (carbonyl), and $\text{NO}$ (nitrosyl).
• Anionic ligands end in -o; for anions that end in -ide (such as chloride), -ate (such as sulfate), and -ite (such as nitrite), change the endings as -ide, -ido, ate, -ato, ite, -ito.

Examples: chlorido, sulfato, and nitrito.

• Greek prefixes indicate the number of each type of ligand in the complex ion:2-di, 3-tri, 4-tetra, 5-penta, 6-hexa.
• If the ligand already contains a Greek prefix (such as the diinethylenediamine) or if it is polydentate (able to attach at more than one binding site simultaneously), then the following prefixes are used instead 2-bis, 3-tris, 4-tetrakis.
• Ligands are named in alphabetical order, ignoring any Greek prefix.
• If there is an uncertainty in identifying which atom is linked to the metal atom, then k E is added to the name in parentheses, where E denotes the connecting atom (and k is kappa).
• If the complex has an overall negative charge (an anionic complex), the suffix -ate is added to the stem of the metal’s name. If the symbol of the metal originates from a Latin name, then the Latin stem is used followed by the oxidation number of the metal in Roman numerals.
• The name of a coordination compound (as distinct from a complex cation or anion) is built in the same way as that of a simple compound, with the cation named before the anion.

Answer to Problem 9C.2E

The name of the complex ${\left[\text{Cr}{\left(\text{Cl}\right)}_{\text{3}}{\left({\text{NH}}_{\text{3}}\right)}_{\text{2}}\left({\text{OH}}_{\text{2}}\right)\right]}^{\text{+}}$ is Diaamineaquachloridechromium (IV).

Explanation of Solution

• The complex has three ligands that water and amine and chloride, if there is more than one ligand then the ligand is named as in the alphabetical order since there are two ligands of amine it is denoted by the Greek prefix ‘di’.
• If the anionic ligand name ends in ‘ide the ending must be changed as ‘ido’ thus chloride ligand is named as chlorido.
• After naming the ligands the metal must be named with its oxidation number in roman numerals.  The oxidation number of chromium in the complex is +4.

The name of the complex ${\left[\text{Cr}{\left(\text{Cl}\right)}_{\text{3}}{\left({\text{NH}}_{\text{3}}\right)}_{\text{2}}\left({\text{OH}}_{\text{2}}\right)\right]}^{\text{+}}$ is Diaamineaquachloridechromium (IV).

(b)

Interpretation Introduction

Interpretation:

The name of the complex ${\left[\text{Rh}{\left(\text{en}\right)}_{\text{6}}\right]}^{\text{3+}}$ has to be given

Concept Introduction:

Refer to part (a).

Answer to Problem 9C.2E

The name of the complex ${\left[\text{Rh}{\left(\text{en}\right)}_{\text{6}}\right]}^{\text{3+}}$ is tris(ethylenediamine)rhenium (III).

Explanation of Solution

• The ligand is named first since ethylenediamine is bidentate ligand and there are three ligands it is denoted by the Greek prefix ‘tris’.
• After naming the ligand the metal must be named with its oxidation number in roman numerals.  The oxidation number of rhenium in the complex is +3

The name of the complex ${\left[\text{Rh}{\left(\text{en}\right)}_{\text{6}}\right]}^{\text{3+}}$ is tris(ethylenediamine)rhenium (III).

(c)

Interpretation Introduction

Interpretation:

The name of the complex ${\left[\text{Fe}{\left(\text{Br}\right)}_{\text{4}}\left(\text{ox}\right)\right]}^{\text{3-}}$ has to be given.

Concept Introduction:

Refer to part (a).

Answer to Problem 9C.2E

The name of the complex ${\left[\text{Fe}{\left(\text{Br}\right)}_{\text{4}}\left(\text{ox}\right)\right]}^{\text{3-}}$ is tetrabromidooxalatoferrate (III)

Explanation of Solution

• The complex has two ligands that bromide and oxalate, if there is more than one ligand then the ligand is named as in the alphabetical order
• If the anionic ligand name ends in ‘ate’ and ‘ide’ the ending must be changed as ‘o’ and ‘ido’ thus oxalate ligand is named as oxo and bromide is named as bromido.
• After naming the ligands in the parentheses the metal must be named with its oxidation number in roman numerals.  The oxidation number of iron in the complex is +3.  Since, it is an anionic complex Latin name of the metal end in ‘ate’ has to given.

The name of the complex ${\left[\text{Fe}{\left(\text{Br}\right)}_{\text{4}}\left(\text{ox}\right)\right]}^{\text{3-}}$ is tetrabromidooxalatoferrate (III).

(d)

Interpretation Introduction

Interpretation:

The name of the complex ${\left[\text{Ni}\left(\text{OH}\right){\left({\text{OH}}_{\text{2}}\right)}_{\text{5}}\right]}^{\text{2}}{}^{\text{+}}$ has to be given.

Concept Introduction:

Refer to part (a).

Answer to Problem 9C.2E

The name of the complex ${\left[\text{Ni}\left(\text{OH}\right){\left({\text{OH}}_{\text{2}}\right)}_{\text{5}}\right]}^{\text{2}}{}^{\text{+}}$ is pentaaquahydridonickel (III).

Explanation of Solution

• The complex has two ligands that water and hydride, if there is more than one ligand then the ligand is named as in the alphabetical order thus ‘aqua’ ligand is named first since there is five ligands it is denoted by the Greek prefix ‘penta.’
• If the anionic ligand name ends in ‘ide’ the ending must be changed as ‘ido’ thus hydride ligand is named as hydrido
• After naming the ligands in the parentheses the metal must be named with its oxidation number in roman numerals.  The oxidation number of nickel in the complex is +3

The name of the complex ${\left[\text{Ni}\left(\text{OH}\right){\left({\text{OH}}_{\text{2}}\right)}_{\text{5}}\right]}^{\text{2}}{}^{\text{+}}$ is pentaaquahydridonickel (III).