Look up any way
Search by name, CAS number, molecular formula, PubChem CID or a drawn structure. Autosuggestions appear while you type.
Every feature, explained
ChemSearch is a chemistry reference and study app for Android. Here is everything it can do, grouped the same way the app groups it.
Search and discovery
Find a compound by almost anything you know about it, then narrow the results with advanced filters.
Random compound
Pick a random compound from PubChem's 123M+ records and open it like a normal search result.
Advanced search
- Query type, include and exclude terms
- Molecular weight range and charge
- Require 3D data or GHS data
- Result limit and name-contains filtering
- Active-filter count with a clear-all action
Recent searches
History grouped by today, yesterday, 7 days, 30 days and older, with pinning, newest or oldest sorting, per-entry removal and clear-all.
Helpful when it fails
Close-spelling suggestions when a name has no match, and separate messages for throttled, timeout, bad-request, network, server and empty results.
Formula styles
Display formulas in conventional order such as H2SO4 and NaCl, or Hill-system order such as H4N+.
Compound results
One page with identifiers, safety data, descriptions, structures and the extra property data behind a single expander.
Identity and properties
Name, formula, CID, CAS number, molecular weight, condensed and empirical formula, IUPAC name, InChI, InChIKey, SMILES and synonyms.
GHS safety data
Hazard information and pictograms from PubChem when the compound has them.
Descriptions
Descriptions from PubChem, Wikipedia or an AI provider you configure.
Extra PubChem data
Uses, occurrence notes, classification tags, XLogP, polar surface area, exact mass, hydrogen-bond counts and rotatable-bond count, kept behind "Show more information about this substance".
Spectral information
Published experimental spectra from PubChem: NMR, IR, mass spectrometry (GC-MS, LC-MS, MS), UV and Raman, each with reported conditions, peaks and values.
Quick actions
Tap identifiers and quick stats to copy them, favourite the compound, download it for offline use, or jump straight into Isomer Search from its formula.
Structures and the 3D viewer
Structures are shown inline and opened in a native viewer — no WebView involved.
2D structures
2D structure images sit on the compound page and open into a larger view when tapped.
3D models
Drag to rotate, pinch to zoom, pinch-drag to pan, then reset or let it auto-spin. The viewer is built natively in Compose.
Fallback models
When PubChem has no 3D model, ChemSearch can build one from SMILES, InChI or InChIKey. Fallbacks are clearly marked as estimates.
Honest about limits
Ionic solids, metals and crystal-like materials often have no meaningful single molecule, so the app explains that instead of drawing something misleading.
Default structure tab
Choose whether a compound opens on 2D, 3D or whichever tab you last used.
Structure Search entry
Every structure view links back to Structure Search so you can keep working from a molecule you found.
Structure Search
Draw a molecule in a native editor, pick a matching mode, and search PubChem by structure.
Drawing tools
Common atoms plus a full periodic-table picker, multiple bond types, structure templates, charges and CPK-style atom colours.
Editing
Select, drag, undo, redo, delete, clean, duplicate, import, export and share.
Four matching modes
Exact, similar, substructure and superstructure matching, each with a summary of the active mode.
Similarity control
A similarity threshold slider with a fine-grained value selector and a configurable result limit.
Import formats
Paste SMILES, InChI or V2000 MOL input, with hints shown for each format.
Live formula badge
The current sketch shows its formula as you build it, and matching results open in a pop-up dialog.
Isomer Search
Find every compound that shares a molecular formula, with instant analysis of the formula you type.
Instant formula summary
Normalised formula, total atom count, molar mass and degrees of unsaturation update as you type, and invalid input is reported clearly.
Sorting and filtering
Sort by relevance or name, and include or exclude isotope results with a dedicated filter.
Compare from results
Select results for comparison and use the quick copy action on any entry.
Retry friendly
Failed isomer searches use the same typed error handling as normal search and can be retried in place.
Library and offline mode
Keep the compounds you care about on the device, along with reference data that works with no connection.
Favourites and downloads
Save compounds for quick access, or download them for offline viewing. Removing one offers an undo action.
Download quality
Choose Basic, Structures or Complete. A download can include details, 2D image, 3D data, identifiers, descriptions, synonyms, GHS data and source notes.
Long-press actions
On any library card: copy its formula, open the compound on PubChem, or remove it.
Compare Compounds
Compare up to six compounds side by side — formulas, descriptions, identifiers, atom and bond counts, molecular weight and more. Copy individual rows, and clear results without starting over.
Backup and transfer
Export favourites and downloads as CSV or JSON, and restore them on another install or device.
Selection sources
Favourites, downloads, supported database entries and ions can all be selected for comparison.
Periodic Table
All 118 official elements, with search, filtering, full detail pages and element trends.
Browse and filter
Element search and interactive category filtering, with quick dialogs and full detail pages.
Element detail
Wikipedia summaries, element images, electron-shell diagrams and both short and full electronic configurations.
Physical properties
Electronegativity, atomic radius, ionization energy, melting and boiling points, density and molar heat.
Spectral lines
Element spectral-line images alongside the number data.
Trends view
Electronegativity, atomic radius, ionization energy, density, melting point and boiling point trends on a blue-to-orange heatmap with a min/max legend and a top-five strip.
Your temperature unit
Trends follow the app's temperature setting: Kelvin, Celsius or Fahrenheit.
Offline chemical database
A bundled reference library that needs no connection at all.
- 01 1,532 Substances
- 02 211 Ions
- 03 122 Functional groups
- 04 326 Reactions
Search and filter
Look up entries by name, alias or formula and filter by entry type.
What is inside
Acids, salts, organic families, polymers, alloys, drugs, dyes, biomolecules and other common chemistry references.
Shared with tools
The reaction entries in the database also power the Reaction Predictor.
No duplication
The 118 elements live in the Periodic Table, so they are not repeated in the substance list.
That is 2,191 bundled entries in total, and none of them need a network connection to open.
Chemistry tools
15 tools across four categories, all usable without a connection.
Molar Mass Calculator
Parse a formula and get its molar mass.
Empirical Formula Finder
Work from composition data or a molecular formula.
Oxidation State Finder
Find oxidation states of each element, including peroxides, superoxides, hydrides and mixed-valence cases.
pH / pOH Calculator
Convert between pH, pOH, [H+] and [OH-].
Dilution Calculator
Solve C1V1 = C2V2 for solutions.
Ideal Gas Law
Solve PV = nRT for gases.
Compare Compounds
Compare up to six compounds side by side.
Reaction Balancer
Balance a chemical equation automatically.
Precipitate Predictor
Predict likely precipitates and net ionic equations from two salts.
Reaction Predictor
Predict products, type, observations and conditions.
Limiting Reagent
Find the limiting reagent, mole ratios, theoretical yield, consumption, leftovers and atom economy.
Percent Yield
Compare actual against theoretical yield.
Reaction Scaling
Scale reactants for a target product amount.
SMILES Visualizer
Paste SMILES to view its 2D and 3D structure.
Custom 3D Molecule Viewer
Load local .sdf or .mol files and view them in 3D.
Home screen and shortcuts
Two widgets and quick launcher shortcuts, all working offline.
Compound of the Day widget
Picks the same compound for a given date on every device using the calendar and the bundled database, and changes at local midnight.
Random Compound widget
Shows a random substance with a refresh button, and avoids showing the same pick twice in a row.
Real formula rendering
Widgets render formulas with Unicode subscripts and superscripts, and tapping one opens Search with that compound.
Launcher shortcuts
Long-press the app icon for Search, Library, Tools and Settings.
Appearance and language
Make the app look the way you want, in the language you want.
Light and dark themes
A light theme and a dark theme, plus AMOLED mode for true-black backgrounds in any colour scheme.
Five colour schemes
Blue, Violet, Emerald, Rose and Amber. Try them in the preview below.
Comfort options
Compact mode, reduce motion, high-contrast outlines, cards mode for flatter surfaces, and haptic feedback.
Temperature unit
Kelvin, Celsius or Fahrenheit, applied across properties and trends.
16 languages
The picker shows each language in its own name, and translations cover the UI, tools, dialogs and widgets.
English
বাংলা
Dansk
Deutsch
Ελληνικά
Español
Suomi
Français
Italiano
日本語
Nederlands
Norsk
Polski
Português
Русский
Svenska
Community translated
Translations are maintained with the help of Crowdin, so new strings reach every language over time.
Colour scheme preview
Showing the Blue scheme in dark mode
Settings, updates and about
Control search behaviour, storage and updates, and see what changed in each version.
Search and data
Autosuggestions, default description source, default structure view, formula style, offline download quality and cache location.
Cache control
A cache size limit of 10 MB, 50 MB, 100 MB or unlimited, with an auto-clear schedule of daily, weekly, monthly or manual.
Backups
Import and export settings, and export the Library as CSV or a JSON backup.
In-app updates
GitHub builds can check for new releases, notify you, download the APK with progress and show an install prompt when it finishes.
About and What's New
App links, credits, license, privacy notes and a collapsible What's New section for the current version.
Optional AI descriptions
Google Gemini, Groq Cloud, OpenAI, OpenRouter and Mistral can be configured, with model lists you can refresh and per-provider model choice.
Privacy, data sources and accuracy
What leaves the device, what stays on it, and where the data comes from.
Privacy
- No analytics and no tracking
- No app-owned server
- History, favourites, downloads, settings and cache stay on the device
- API keys are encrypted locally with Android Keystore
- Drawn structures are sent to PubChem only when you use Structure Search
Data sources
- PubChem PUG REST and PUG View
- UNECE GHS pictograms
- Wikipedia and Wikimedia Commons
- NCI/CADD fallback structures
- Bundled local JSON chemistry data
Accuracy and limits
ChemSearch is a study and reference tool, not a replacement for official safety documentation. PubChem and Wikipedia results depend on those services, AI text should be checked, and fallback 3D models are estimates.
Open source
MIT licensed. Built with Kotlin, Jetpack Compose and Material 3, with Room, DataStore, WorkManager, Retrofit, OkHttp, Gson and Coil.
Try it on your phone
Free and open source for Android 8.0 and newer. Grab the latest build from GitHub or F-Droid.
