Inorganic · Cages & Clusters
Cages & Clusters
Exam-focused revision notes on Cages & Clusters for CSIR-NET Chemical Sciences, GATE Chemistry and IIT-JAM — the core concepts, the formulas worth memorising, the traps that cost marks, and a quick-recall table.
The core idea
Cage and cluster compounds (boranes, carboranes, metal carbonyl clusters) are electron-deficient — they cannot be described by simple 2-centre-2-electron bonds alone. Instead we count the skeletal electrons shared across the whole framework and use that count to predict the shape.
What this note covers
- 1The core idea
- 2Borane classification (increasingly open)
- 3Wade's Rules (PSEPT)
- 4Counting skeletal electrons
- 5Carboranes
- 6Structural relationship (closo → nido → arachno)
- 7Metal clusters & the isolobal analogy
- 8Common traps students miss
- 930-second recall table
Read the full note
The remaining 8 sections — including the worked examples, the common-traps list and the quick-recall table — are part of ChemVidya Full Access, along with 6,000+ practice questions.
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