Chapter 22, Problem 22.82QP

(a)

Interpretation Introduction

Interpretation:

For the complex ${\left[Co{F}_6\right]}^{3-}$, the following have to be determined –

1. (a) Geometry of complex ion
2. (b) Color absorption in whether red or blue
3. (c) Whether high spin or low spin complex

Concept Introduction:

Complex compounds are primarily formed by transition elements which are d-block elements.  A co-ordination compound is known as a complex compound is made of metal atom/ion and ligand(s).  Ligands are considered as Lewis bases and the central metal atom is Lewis acid.  Ligands donate a pair of electron to metal ion and establishes bonding with metal ion which is known as co-ordinate bond and hence these compounds are named as co-ordination compounds.  The ligands represented inside the square brackets.

Complex compounds exist in following geometries - tetrahedral, square planar, octahedral etc.

Spectrochemical series refers to the arrangement of ligands with respect to crystal field splitting they cause in the d-orbitals of a metal ion.  The ligand that causes larger splitting pattern is referred to as stronger ligand.

The ligands are arranged in increasing order of crystal field splitting they produce.

$\begin{array}{l}{I}^{-}<B{r}^{-}<S^{2-}<SC{N}^{-}<C{l}^{-}<N{O}_3{}^{-}<N_3{}^{-}<F^{-}<O{H}^{-}<C_2{O}_4{}^{2-}<H_{2}O<NC{S}^{-}\\ <C{H}_{3}CN<py<N{H}_3<en<bipy<phen<N{O}_2{}^{-}<PP{h}_3<C{N}^{-}<CO\end{array}$

The ligand that causes larger crystal field splitting is strong ligand and the ligand that causes smaller splitting is termed as weak ligand.

Depending upon magnetic property Complexes are of two types - low spin complex and high spin complex. A complex is said to be low-spin if it doesn't have unpaired electrons whereas in high spin complex there will be presence of unpaired electrons.  Stronger ligands pair the electrons and produce diamagnetic, low-spin complexes. Weaker ligands are incapable of pairing the electrons and form paramagnetic, high-spin complexes.

Almost all the Co-ordination compounds are colored compounds.  Presence of unpaired electrons in a complex compound makes it colored as the unpaired electrons undergo transition from lower energy level to higher energy level.  The color of the complex observed is complementary to the color absorbed in the wavelength region.

Answer to Problem 22.82QP

The complex ion is octahedral in geometry.

Explanation of Solution

The complex ion ${\left[Co{F}_6\right]}^{3-}$ has six fluoro ligands.  Hence, the co-ordination number is six and so the geometry of the complex would be octahedral.

(b)

Interpretation Introduction

Interpretation:

For the complex ${\left[Co{F}_6\right]}^{3-}$, the following have to be determined –

1. (a) Geometry of complex ion
2. (b) Color absorption in whether red or blue
3. (c) Whether high spin or low spin complex

Concept Introduction:

Complex compounds are primarily formed by transition elements which are d-block elements.  A co-ordination compound is known as a complex compound is made of metal atom/ion and ligand(s).  Ligands are considered as Lewis bases and the central metal atom is Lewis acid.  Ligands donate a pair of electron to metal ion and establishes bonding with metal ion which is known as co-ordinate bond and hence these compounds are named as co-ordination compounds.  The ligands represented inside the square brackets.

Complex compounds exist in following geometries - tetrahedral, square planar, octahedral etc.

Spectrochemical series refers to the arrangement of ligands with respect to crystal field splitting they cause in the d-orbitals of a metal ion.  The ligand that causes larger splitting pattern is referred to as stronger ligand.

The ligands are arranged in increasing order of crystal field splitting they produce.

$\begin{array}{l}{I}^{-}<B{r}^{-}<S^{2-}<SC{N}^{-}<C{l}^{-}<N{O}_3{}^{-}<N_3{}^{-}<F^{-}<O{H}^{-}<C_2{O}_4{}^{2-}<H_{2}O<NC{S}^{-}\\ <C{H}_{3}CN<py<N{H}_3<en<bipy<phen<N{O}_2{}^{-}<PP{h}_3<C{N}^{-}<CO\end{array}$

The ligand that causes larger crystal field splitting is strong ligand and the ligand that causes smaller splitting is termed as weak ligand.

Depending upon magnetic property Complexes are of two types - low spin complex and high spin complex. A complex is said to be low-spin if it doesn't have unpaired electrons whereas in high spin complex there will be presence of unpaired electrons.  Stronger ligands pair the electrons and produce diamagnetic, low-spin complexes. Weaker ligands are incapable of pairing the electrons and form paramagnetic, high-spin complexes.

Almost all the Co-ordination compounds are colored compounds.  Presence of unpaired electrons in a complex compound makes it colored as the unpaired electrons undergo transition from lower energy level to higher energy level.  The color of the complex observed is complementary to the color absorbed in the wavelength region.

Answer to Problem 22.82QP

The complex will absorb in red region.

Explanation of Solution

The complex ion ${\left[Co{F}_6\right]}^{3-}$ has fluoro ligands.  As spectrochemical series indicates fluoro ligands as weak ligands, it has smaller crystal field splitting energy so that the complex containing fluoro ligands absorb in higher wavelength region which is red.  Red color has greater wavelength than blue color.

(c)

Interpretation Introduction

Interpretation:

For the complex ${\left[Co{F}_6\right]}^{3-}$, the following have to be determined –

1. (a) Geometry of complex ion
2. (b) Color absorption in whether red or blue
3. (c) Whether high spin or low spin complex

Concept Introduction:

Complex compounds are primarily formed by transition elements which are d-block elements.  A co-ordination compound is known as a complex compound is made of metal atom/ion and ligand(s).  Ligands are considered as Lewis bases and the central metal atom is Lewis acid.  Ligands donate a pair of electron to metal ion and establishes bonding with metal ion which is known as co-ordinate bond and hence these compounds are named as co-ordination compounds.  The ligands represented inside the square brackets.

Complex compounds exist in following geometries - tetrahedral, square planar, octahedral etc.

Spectrochemical series refers to the arrangement of ligands with respect to crystal field splitting they cause in the d-orbitals of a metal ion.  The ligand that causes larger splitting pattern is referred to as stronger ligand.

The ligands are arranged in increasing order of crystal field splitting they produce.

$\begin{array}{l}{I}^{-}<B{r}^{-}<S^{2-}<SC{N}^{-}<C{l}^{-}<N{O}_3{}^{-}<N_3{}^{-}<F^{-}<O{H}^{-}<C_2{O}_4{}^{2-}<H_{2}O<NC{S}^{-}\\ <C{H}_{3}CN<py<N{H}_3<en<bipy<phen<N{O}_2{}^{-}<PP{h}_3<C{N}^{-}<CO\end{array}$

The ligand that causes larger crystal field splitting is strong ligand and the ligand that causes smaller splitting is termed as weak ligand.

Depending upon magnetic property Complexes are of two types - low spin complex and high spin complex. A complex is said to be low-spin if it doesn't have unpaired electrons whereas in high spin complex there will be presence of unpaired electrons.  Stronger ligands pair the electrons and produce diamagnetic, low-spin complexes. Weaker ligands are incapable of pairing the electrons and form paramagnetic, high-spin complexes.

Almost all the Co-ordination compounds are colored compounds.  Presence of unpaired electrons in a complex compound makes it colored as the unpaired electrons undergo transition from lower energy level to higher energy level.  The color of the complex observed is complementary to the color absorbed in the wavelength region.

Answer to Problem 22.82QP

The complex is high spin complex.

Explanation of Solution

Referring to spectrochemical series fluoro ligand is a weak ligand.  Hence, it forms high spin complex.  Therefore ${\left[Co{F}_6\right]}^{3-}$ is high spin complex.