Coordination Chemistry
The deepest treatment of coordination chemistry ChemVidya has written. It builds the subject in the order it was discovered — the evidence first, then valence bond theory, then crystal field, then the molecular-orbital picture that explains why crystal field works at all — and finishes on spectra, magnetism, stability, kinetics and the bioinorganic applications the paper keeps returning to.
- 9 parts
- 87 sections
- ~176,570 words
- 9 free extracts — one per part
- CSIR-NET · GATE · IIT-JAM
What you can read without paying
Every one of the 9 part pages below reproduces its opening section in full — the real text, the real figures — before the paywall. That is 9 complete sections of Coordination Chemistry, free, with no sign-in.
Foundations, Nomenclature & Structural Isomerism
The first part of the deepest treatment of coordination chemistry ChemVidya has attempted. It deliberately contains no bonding theory : Werner’s framework and the evidence that forced it, the vocabulary of the coordination sphere, ligand classification and the chelate effect, oxidation state and electron counting, coordination number and…
- Werner’s two valences
- The two experiments that decide a formulation
- The coordination sphere, and the vocabulary that goes with it
- Ligands — how they are classified and why it matters
- Chelation and the chelate effect
- Oxidation state and the d-electron count
- EAN and the 18-electron rule
- Coordination number and geometry
- Naming a coordination compound
- Writing the formula
- Ionisation and hydrate isomerism
- Coordination and coordination-position isomerism
- Linkage isomerism
- The nine parts at a glance
Stereochemistry & Isomer Counting
Part 1 described which atoms are bonded to which. This part describes how those bonds are arranged in space — and why that arrangement can be the difference between a cancer drug and an inactive compound. It covers cis / trans and fac / mer geometrical isomerism, a systematic method for counting isomers that works every time, chirality…
- Geometrical isomerism — cis/trans and fac/mer
- Counting isomers systematically
- Chirality at a metal centre — Λ and Δ
- Conformational isomerism of chelate rings
- Resolution and racemisation
- Telling the isomers apart in the laboratory
Valence Bond & Crystal Field Theory
Parts 1 and 2 described coordination compounds completely without explaining a single thing about them. This part begins the explanation. It follows the two models in the order history produced them: valence bond theory , which gets the shapes right and the colours hopelessly wrong, and crystal field theory , which throws away covalency…
- Valence bond theory — hybridisation and the dative bond
- What valence bond theory cannot do
- The crystal field model and the octahedral splitting
- Tetrahedral, tetragonal and square-planar fields
- Crystal field stabilisation energy
- High spin and low spin — the Δ versus P criterion
- The spectrochemical series — of ligands and of metals
- Jahn–Teller distortion and the thermodynamic evidence
Ligand Field & Molecular Orbital Theory
Crystal field theory works far better than a model that pretends bonds are electrostatic has any right to. This part explains why it works, by replacing the point charges with real orbitals. Building the ML₆ molecular orbital diagram properly turns Δ o from an unexplained parameter into the gap between a bonding and an antibonding set —…
- The evidence that the bonding is covalent
- Symmetry-adapted combinations of the six ligand σ orbitals
- The σ-only ML₆ diagram, and what Δo really is
- π-donor ligands — why halides give small splittings
- π-acceptor ligands, and the series derived
- Synergic bonding in metal carbonyls, and the infrared proof
- The nephelauxetic effect — covalency, measured
- Non-innocent ligands and the collapse of oxidation state
- The 18-electron rule from the MO diagram, and the 16-electron square plane
- Where this leads — a pointer to Part 5
Electronic Spectra
This is the part that turns a coloured solution into a number. It builds the free-ion term symbols from first principles by counting microstates, follows each term into the ligand field, and then uses Orgel and Tanabe–Sugano diagrams to assign the bands of a real spectrum and extract Δ o and the Racah parameter B from them. It also…
- Electron–electron repulsion: the term nobody drew
- Microstates and Russell–Saunders terms
- Ground terms, Hund’s rules and the full term tables
- How each term splits in an octahedral field
- Orgel diagrams
- Tanabe–Sugano diagrams
- Selection rules and the intensity of a band
- Charge transfer, Racah B and the nephelauxetic effect
- Capstone — extracting Δo and B from a measured spectrum
- Where this leads — Part 6
Magnetism
Magnetism is the most reliable experimental handle on a complex’s electronic structure, and the place where students most often stop at a single memorised formula. This part starts at that formula, shows exactly which complexes obey it and which do not, and then explains the failures — orbital contribution, spin–orbit coupling…
- Diamagnetism, paramagnetism, ferromagnetism — and the sign and size of χ
- The spin-only formula, the dn table, and what real complexes actually give
- The orbital contribution, quenching, and spin–orbit coupling
- Susceptibility properly defined, and the diamagnetic correction
- Measuring it — Gouy, Faraday, SQUID and the Evans NMR method
- Temperature dependence — Curie, Curie–Weiss and TIP
- Spin-crossover complexes
- Exchange coupling in polynuclear complexes
- Magnetic ordering, and a word on single-molecule magnets
Stability & Thermodynamics
Every complex in this book exists only to the extent that an equilibrium constant allows it to. This part is about those constants: how they are defined, why they almost always fall as more ligands are added, how they are measured, and what controls their size. It treats the chelate and macrocyclic effects quantitatively rather than as…
- Stepwise constants Kn, overall constants βn, and moving between them
- Why K₁ > K₂ > K₃ … — and the instructive cases where it is not
- Measuring stability constants — pH titration, spectrophotometry and Job’s method
- Metal-ion factors — charge, size and the Irving–Williams series
- Ligand factors — basicity, ring size, sterics and π-bonding
- Hard and soft acids and bases, applied properly
- The chelate effect quantified
- The macrocyclic and cryptate effects, and preorganisation
- Conditional constants, masking and the EDTA titration
Reaction Mechanisms & Kinetics
A complex can be thermodynamically unstable and sit unchanged on the shelf for years, or be perfectly stable and exchange its ligands a million times a second. This part is about that second axis — rate rather than position — and it is where coordination chemistry becomes predictive. It covers why some centres are inert, how ligands are…
- K.1 Stable is not the same word as inert
- K.2 Crystal field activation energy — why d³ and low-spin d6 are inert
- K.3 D, A and I — naming the mechanism and proving which it is
- K.4 Octahedral substitution — acid hydrolysis, base hydrolysis, anation and stereochemistry
- K.5 Square-planar substitution — the two-term rate law
- K.6 The trans effect — choosing which isomer you get
- K.7 Outer-sphere transfer, the Franck–Condon restriction and Marcus theory
- K.8 Inner-sphere transfer — Taube’s experiment
- K.9 Photochemistry of coordination compounds — a short introduction
Applications & Special Topics
The last part answers the question a student is entitled to ask after eight parts of theory: what is any of this for. Haemoglobin is a coordination compound whose behaviour is a spin-state change. Cisplatin is a substitution reaction with a trans -effect synthesis and a kinetic-inertness rationale. An industrial catalytic cycle is…
- L.1 Oxygen transport and storage — a spin-state change with consequences
- L.2 Other metalloproteins read as coordination compounds
- L.3 Metallodrugs — cisplatin, contrast agents and chelation therapy
- L.4 The elementary steps, with the electron count tracked throughout
- L.5 Three catalytic cycles, worked vertex by vertex
- L.6 Metal–metal bonds, the δ bond, and clusters
- L.7 Crown ethers, cryptands and size-match selectivity
- L.8 Self-assembly and metal–organic frameworks
- L.9 Molecular recognition — and where the subject goes next
- Section-by-section index
- The argument, from Part 1 to Part 9
- The nine parts
Read all 87 sections
Coordination Chemistry in full — all 9 parts, every worked example, every figure — is part of ChemVidya Full Access, along with the other books, 55 Study Notes and 6,000+ practice questions.
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