The world's most demanding chemistry competition. IChO spans all branches at undergraduate depth — physical, inorganic, organic, analytical — in a 5-hour theoretical exam. Prepare with free advanced simulators and official prep problems.
Physical chemistry — kinetics, thermodynamics, and electrochemistry combined — makes up over 50% of every IChO problem set we analyzed. Analytical chemistry alone is ~20% of preparatory problems, while coordination chemistry — often assumed to be a headline IChO topic — barely registers. If you're prioritizing study time, physical chemistry depth and analytical technique matter far more than coordination chemistry memorization.
Official pre-competition problem sets, by domain · n = 222 questions
Multi-year compiled official problem collections · n = 39 questions
Advanced Interactive Labs
30+ simulators covering IChO-level topics — crystal field theory, coordination chemistry, thermodynamics, electrochemistry, stereochemistry, organic mechanisms, quantum chemistry, and more.
Browse All Simulations →Interactive Study Guide
The Advanced Chemistry interactive ebook — 7 chapters covering exactly what IChO tests beyond AP/Orgo level: analytical chemistry, advanced kinetics, thermodynamics, equilibrium, electrochemistry, spectroscopy, and solid state.
Open Ebook →Prep Problems & Past Papers
Official IChO preparatory problems (2001–2025) with model solutions, marking schemes, and topic-filtered browsing. Build the problem-solving depth IChO demands.
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