Chembook vs ATC
Price, ratings, monetisation and update history for both apps, side by side β with what reviewers say about each.
Chembook
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Chembook is an offline chemistry reference built around things you can turn, step through, and take apart. REACTION MECHANISMS IN 3D Step through 128 reaction mechanisms frame by frame, with curved electron-pushing arrows drawn on the actual atoms. Explore quantum-optimized structures alongside teaching models of the steps between them. Switch between the 3D model and a clean 2D skeletal depiction. ADVANCED TOPICS Explore six interactive lessons: collision theory, potential energy surfaces, WoodwardβHoffmann rules, crystal field and JahnβTeller effects, Walsh diagrams, and band theory. Follow reaction trajectories across energy landscapes. Change molecular geometry to see orbital energies shift, explore spin and distortion, and watch discrete energy levels become bands. ATOMIC & MOLECULAR ORBITALS Rotate orbital isosurfaces in 3D, from s, p, d and f atomic orbitals to computed molecular orbitals. Explore their shapes, nodes and wavefunction signs. SPECTROSCOPY REFERENCE 1H and 13C NMR shift tables, IR and Raman bands, mass spectrometry and UV-Vis, with tappable reference entries that place peaks on a live spectrum. Includes an interactive n+1 splitting-tree tool. MOLECULAR DYNAMICS LAB Run interactive molecular simulations on your device. Explore argon, water and ionic systems, adjust temperature and density, and watch molecular motion and the radial distribution function update as the simulation runs. STRUCTURES & CONFORMERS Chair flips, anomers, amino acids, unit cells and framework solids in 3D, with a Ramachandran plot and potential-energy scans you can drag. PERIODIC TABLE All 118 elements with trends, a comparison view and detailed properties. QUIZ Seven modes: periodic table, compound hunt, reaction mechanisms, spectra identification, vibrational mode matching, nomenclature, and amino acids. BUILT FOR OFFLINE STUDY All reference content, lessons and visualizations work offline. No Chembook account, no sign-in, no analytics, no ads and no personal data collection. Your notes and study progress stay on your device. An internet connection is needed for purchases and restores. FREE AND PRO 20 core reaction mechanisms, the full periodic table, all spectroscopy reference, orbitals, structures, and the molecular dynamics lab are free. A single one-time purchase unlocks the remaining 108 mechanisms, all six Advanced Topics lessons and unlimited quiz play.
ATC
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This is the official ATC18 app. [Main Features] - View schedule - Search sessions & papers - Notifications for favorite sessions and papers - Other conference information [Inquiries] The Korean Fiber Society Email: k@fiber.or.kr, p@fiber.or.kr Website: https://fiber.or.kr Experience a smarter academic conference with the newly improved ATC-18 app!
Screenshots
Verdict
The clearest difference is in-app purchases: ATC at none against Chembook's 1. ATC also leads on update cadence (every 5 days vs every 3 weeks). On price, ads, device support and iOS requirement there is nothing between them.
Scored on Price Β· Rating Β· Positive reviews Β· Number of ratings Β· Update frequency Β· Ads Β· In-app purchases Β· Monetization Β· Best chart rank Β· Devices Β· Requires iOS
Both are free to download. Chembook sells 1 one-off in-app purchase. ATC asks for nothing beyond the download.
Chembook ships an update every 3 weeks, ATC every 5 days. The most recent releases landed on October 15, 2026 and October 29, 2026 respectively.
| Parameter | Chembook | ATC |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 3 weeks | Every 5 days β better |
| Ads | No | No |
| In-app purchases | Yes | No β better |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 17.0 | 16.4 β better |
| Further details β not scored | ||
| Size | 110 MB | 63 MB |
| Age rating | 4+ | 4+ |
| Developer | Hyuk-Yong Kwon | ThinkonWeb Inc. |
In-app purchases
Chembook
- Pro$6.99
ATC
No in-app purchases









