Werner Theory | Definition, Postulates, Examples & Applications

Introduction to Werner Theory

Alfered Werener, a Swiss chemist, proposed Werner’s Theory of Coordination Compounds in 1898. Werner investigated the physical, chemical, and isomeric aspects of many coordination molecules and proposed some hypotheses.

We shall learn about Werner Coordination theory, its postulates, and others in depth in this article.

Werner coordination theory and Postulates of werner’s theory

Werner proposed his coordination compound hypothesis in 1898. The main tenets of Werner’s theory of coordination compounds pdf are as follows:

1. Metals in coordination compounds have two sorts of linkages (valences): primary and secondary.
2. Negative ions satisfy the primary valances that are ionisable in general.
3. Secondary valences are not ionisable. These requirements are met by neutral molecules or negative ions. The secondary valence of a metal is equal to the coordination number and is constant.
4. Secondary connections connect ions/groups to metals, which have diverse spatial configurations that correlate to different coordination numbers.
5. In modern formulations, such spatial groupings are referred to as coordination polyhedra.
6. The ions outside the square bracket are referred to as counter ions, whereas the species within the square bracket are referred to as coordination entities or complexes.

Werner coordination number

The werner coordination number (CN) is the number of ligand donor atoms to which a metal ion in a complex is directly bonded.

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Werner theory examples

The Werner theory examples are as follows:

• [Co(NH3)6]Cl3
  There are three ionizable primary bonds in this, which are satisfied by Cl- ion, also known as Counter ion, which is represented outside the square bracket. The number of secondary valencies is six, which is met by neutral NH3 molecules and written inside the square bracket. The form of the molecule is determined by these six secondary valences.

• [CoCl(NH3)5]Cl2
  There are two main bonds in this that are ionizable and can be fulfilled by Cl- ion, also known as Counter ion, which is illustrated outside the square bracket. The number of secondary valencies is six, which is satisfied by five neutral NH3 molecules and one Cl atom, and is written inside the square bracket. The form of the molecule is determined by these six secondary valences.

Application of werner theory of coordination compounds pdf

The applications of Werner theory of coordination compounds are listed below:

1. It was capable of predicting the precise formulation of each complex.
2. It was able to describe the behavior (various attributes) of each complex and indicate why different complexes of the same metal atom and ligand behaved differently.
3. It was capable of predicting the structures of several complexes with coordination numbers 4 (tetrahedron or square planar) and 6 (octahedral).
4. It could explain the presence of isomerism in inorganic compounds (other than because of the presence of carbon). In coordination compounds, it might anticipate both geometrical (cis and trans) and optical isomerism.
5. It has the potential to anticipate other types of isomerism in coordination compounds, such as ionization or coordination isomerism, which differ from both geometrical and optical isomerism.

Frequently Asked Questions on Werner Theory

Explain werner's theory of coordination compounds pdf.

Werner developed a theory to explain the coordination compounds' structures, production, and bonding nature. Werner's theory of coordination compounds is the name given to this hypothesis.

Write four postulates of werner's theory of coordination compounds pdf?

The following are the key postulates of Werner's theory: In coordination compounds, the core metal or metal atoms exhibit two types of valency: primary valency and secondary valency. The main valency is represented by the oxidation state, whereas the secondary valency is represented by the coordinate number.

Which chapter is Werner Theory Class 12?

Chapter 9 Werner Theory | Coordination Chemistry | Chapter 9 | NCERT Class 12

Who is the father of Werner theory of coordination compounds?

Alfred Werner (December 12, 1866–November 15, 1919) was a Swiss chemist who studied at ETH Zurich and taught at the University of Zurich. In 1913, he was awarded the Nobel Prize in Chemistry for suggesting the octahedral structure of transition metal complexes.

What is an example of a Werner complex?

Werner theory examples are as listed below: CoCl3. 6NH3 Complex: The coordination number of cobalt in this compound is 6, and NH3 molecules satisfy all six secondary valencies. CoCl3. 5NH3 complex: Cobalt has a coordination number of 6 in this chemical.