Werner's Coordination Theory of Coordination Compounds

Alfred Werner in 1898 proposed Werner's Coordination Theory of Coordination Compounds. Important postulates, Pictorial Representation, Primary and Secondary valency, NEET JEE Previous year Questions.

Werner's coordination theory and it's experimental verification:

In 1893, Werner was the first to propose correct structures for coordination compounds containing complex ions , in which a central transition metal atom is surrounded by neutral or anionic ligands .

CoCl3•6NH3 This type of representation does not implies any proper geometry around the central metal ion

The basic postulates of Werner's coordination theory may be summerised as follows:

1. In co-ordination compounds, central metal atoms exhibit primary valency and secondary valency.

The primary valency is ionizable. Secondary valency is not ionizable.The primary valency corresponds to oxidation state.The secondary valency corresponds to coordination number. (the central metal ion and ligands are not ionizable)

2. Every metal atom has a fixed number of secondary valencies (coordination number(s)).

3. The metal atom tends to satisfy boths its primary valency as well as its secondary valency. Primary valency is satisfied by negative ions (metal ion has a positive charge) whereas secondary valency (coordination number) is satisfied either by negative ions or by neutral molecules. (In certain case a negative ion may satisfy both types of valencies).

4. The coordination number or secondary valencies are always directed towards the fixed positions in space and this leads to definite geometry of the coordination compound.

Examples Based on Postulates of Werner’s Coordination Theory

Structures of various cobalt ammines is based on Werner’s Coordination Theory is given below:

Cobalt has a primary valency (oxidation state) of three and exhibit secondary valency (coordination number) of 6. The secondary valencies are represented by thick lines and the primary valency is represented by broken lines.

[1] CoCl3.6NH3 Complex: In this compound, the coordination number of cobalt is 6 and all the 6 secondary valencies are satisfied by NH3 molecules (the black solid lines). The 3 primary valencies are satisfied by chloride ions (the dotted line in fig). These are non-directional in character. These chloride ions are instantaneously precipitated on the addition of silver nitrate. The total number of ions in this case is 4, three chloride ions and one complex ion. The central ion and the neutral molecules or ions satisfying secondary valencies are written in a square bracket while writing the formula of the compound. Hence the complex may be written as [Co(NH3)6]Cl3 and as shown as in fig.
CoCl3.6NH3 Complex

 CoCl3.5NH3 Complex: In this compound, cobalt has the coordination number of 6. However, we see that the number of NH3molecule decreases to 5. The chloride ion occupies the remaining one position. This chloride ion exhibits the dual behaviour as it has primary as well as secondary valency.
Werner's Theory CoCl3.5NH3 Complex

[3] ​​​​​CoCl3.4NH3 complex: In this compound, two chloride ions exhibit dual behaviour of satisfying both Primary and Secondary Valencies. This compound will give precipitate with silver nitrate corresponding to only one Cl- ion and the total number of ions in this case is 2. Hence it can be formulated as [CoCl2(NH3)4]Cl.
CoCl3.4NH3 complex
1.     W. Gregory Jackson; Josephine A. McKeon; Silvia Cortez (2004). "Alfred Werner's Inorganic Counterparts of Racemic and Mesomeric Tartaric Acid: A Milestone Revisited". Inorg. Chem. 43 (20): 6249–6254. doi:10.1021/ic040042e. PMID 15446870.
2.     Kristin Bowman-James (2005). "Alfred Werner Revisited: The Coordination Chemistry of Anions". Acc. Chem. Res. 38 (8): 671–678. doi:10.1021/ar040071t. PMID 16104690.
3.     Miessler, Gary L.; Donald Arthur Tarr (1999). Inorganic Chemistry. p. 642. ISBN 978-0-13-841891-5.
4.     "Coordination Compound".
5.    Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
6.     ^ Angelo R. Rossi; Roald. Hoffmann (1975). "Transition metal pentacoordination". InorganicChemistry14 (2): 365–374. doi:10.1021/ic50144a032.
7.     Harris,, D.; Bertolucci, M. (1989). Symmetry and Spectroscopy. Dover Publications.
8.     ^ Cotton, F. AlbertWilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999), 
9.     von Zelewsky, A. "Stereochemistry of Coordination Compounds" John Wiley: Chichester, 1995. ISBN 047195599.
10. ^ Miessler, Gary L.; Donald Arthur Tarr (1999). "9". Inorganic Chemistry. pp. 315, 316. ISBN 978-0-13-841891-5.

werner's theory class 12
application of werner theory
state and explain werner's theory of coordination compound with suitable example
primary valency is ionisable
evidence of werner theory
Page navigation



01 Solid State,3,01 Some Basic Concepts of Chemistry,4,02 Solutions,1,02 Structure of Atom,2,03 Electrochemistry,1,03 Periodicity of Elements,1,04 Chemical Bonding,7,04 Chemical Kinetics,1,05 Gaseous State of Matter,1,05 Surface Chemistry,2,06 Chemical Thermodynamics,3,07 Equilibrium,7,07 p Block Elements,7,08 d and f Block Elements,1,08 Redox Reaction,1,09 Coordination Compounds,1,09 Hydrogen Chemistry,1,10 Haloalkanes and Haloarenes,1,10 s block Elements,1,11 Alcohols Phenols and Ethers,2,11 Some p block Elements,2,12 Aldehyde Ketones and Carboxylic Acids,4,12 Basic Organic Chemistry,1,13 Hydrocarbons Chemistry,1,13 Nitrogen Containing,3,14 Biomolecules,3,14 Environmental Chemistry,2,15 Polymer chemistry,1,16 Chemistry in Everyday life,2,20,6,2O,1,Acids Bases and Salts,1,Alcohols,1,Alcohols Phenols and Ethers Question Bank,2,Atomic Structure Question Bank,1,Basic Principles of Organic Chemistry Question Bank,1,Biomolecules Question Bank,1,Carbonyl Compounds Question Bank,2,CBSE 11,1,CBSE 12,2,CBSE Class 10 Chemistry,2,Chemical Equilibrium Question Bank,2,Chemical Kinetics Question Bank,1,Chemical Thermodynamics Question Bank,3,Chemical Weapons,1,Chemistry Book,1,Chemistry News,1,Chemistry Song,2,Chemistry Syllabus,2,Class 11,1,Class 11 Chemistry,1,Class 8 Science,1,Condensation reaction,1,COVID-19,4,Download NEET Question Papers,2,Electrochemistry,1,Electrochemistry MCQs,1,Electrochemistry MCQs with Answers,1,Exclusive Chemistry,1,Food,1,General Chemistry,5,How do I study for chemistry,2,Hydrocarbons Question Bank,1,JEE Main,2,JEE Main Chemistry,2,JEE Main Chemistry Syllabus,1,JEE Main Chemistry Syllabus 2021,1,JEE Main Hydrocarbons Previous Year Questions with Solutions,1,JEE Main Question Paper,2,Lewis dot structures,5,MCQ Practice sheet,6,MCQs with Solution,1,Name Reaction,7,NCERT CBSE Syllabus,1,NCERT Syllabus,1,NEET,8,neet sample paper by nta,1,NEET | AIPMT | JEE Main MCQs,2,NEET 2020 Question Papers,1,NEET Chemistry Syllabus,1,NEET Hydrocarbons Previous Year Questions with Solutions,1,NEET Previous Year Question Paper,4,NEET Previous Year Question Papers,1,NEET Previous Year Solved Question Papers,3,NEET Question Paper,1,NEET Question Papers 2020,1,NEET Sample Papers,1,NEET Solved Question Papers,4,Nitrogen Containing Compound Question Bank,1,Organic Name Reactions,6,Oxidation Reduction,2,p Block Elements Question Bank,4,Phenols and Ethers MCQs,1,Phenols and Ethers MCQs (NEET; JEE Main),1,Practice Paper of NEET,1,Question Papers of NEET 2020,1,Radioactivity,1,s Block Elements,1,s Block Elements MCQs,1,s Block Elements Question Bank,1,Science News,1,Solid State Chemistry Question Bank,2,SOME,1,Study Tips for Chemistry,2,Surface Chemistry Question Bank,2,WBCHSE,1,WBCHSE Model Question,1,
Advanced Chemistry: Werner's Coordination Theory of Coordination Compounds
Werner's Coordination Theory of Coordination Compounds
Alfred Werner in 1898 proposed Werner's Coordination Theory of Coordination Compounds. Important postulates, Pictorial Representation, Primary and Secondary valency, NEET JEE Previous year Questions.
Advanced Chemistry
Loaded All Posts Not found any posts VIEW ALL Readmore Reply Cancel reply Delete By Home PAGES POSTS View All RECOMMENDED FOR YOU LABEL ARCHIVE SEARCH ALL POSTS Not found any post match with your request Back Home Sunday Monday Tuesday Wednesday Thursday Friday Saturday Sun Mon Tue Wed Thu Fri Sat January February March April May June July August September October November December Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec just now 1 minute ago $$1$$ minutes ago 1 hour ago $$1$$ hours ago Yesterday $$1$$ days ago $$1$$ weeks ago more than 5 weeks ago Followers Follow THIS PREMIUM CONTENT IS LOCKED STEP 1: Share. STEP 2: Click the link you shared to unlock Copy All Code Select All Code All codes were copied to your clipboard Can not copy the codes / texts, please press [CTRL]+[C] (or CMD+C with Mac) to copy