Structo

Potassium Iodide

About this app

Structo is a chemical structure editor built for students, educators, and
anyone who needs to draw clear, accurate chemical structures on the go.
Sketch molecules, reaction schemes, and mechanisms with a fast, intuitive
touch interface — no desktop required.

FEATURES

Structure Drawing
- Draw bonds, rings, and functional groups with the clean, textbook-style
conventions used in published chemical literature
- Automatic valence correction when substituting elements
- Clean Structure tool to instantly tidy up rings and spacing
- Full stereochemistry support: wedge/dash bonds, explicit hydrogens on
stereocenters, and automatic handling of ring vs. exocyclic double bonds

Built-In Templates
Insert ready-made structures from a wide library covering:
- Common rings and scaffolds
- Steroids
- Sugars
- Nucleobases
- Alkaloids and neurotransmitters
- Pharmaceuticals
- Heterocycles
- And more

All templates use standard 2D coordinates, so your structures look
textbook-accurate every time.

Reaction Tools
- Forward and equilibrium reaction arrows
- Curved (mechanism) arrows for showing electron movement
- Lone pair markers
- A reaction-condition picker for common reagents and conditions above and
below the arrow, with subscript/superscript support

Validation Dashboard
- Instantly check your structure for common drawing errors
- Jump directly to flagged issues to fix them one by one
- Turn Auto-Validate on or off depending on your workflow

Analysis & Export
- Molecular formula, molecular weight, and monoisotopic mass calculated
automatically as you draw
- Import and export structures using SMILES notation
- Export your structures as PNG, JPEG, BMP, or TIFF images, or copy them
directly to your clipboard to paste into other apps

Text & Labels
- Add and edit atom labels, including isotope notation with partial
superscript/subscript formatting
- Add text annotations anywhere on the canvas
- Rotate, group, and transform labels and annotations freely

Built-In Tutorial
New to structure drawing apps? A short interactive tutorial walks you
through the basics so you can start drawing right away.

PRIVACY

Structo collects only anonymous, aggregated usage data to help us improve
the app — never the chemical structures you create. See our full privacy
policy for details.

Whether you're studying for an exam, preparing course materials, or just
need to sketch a quick structure, Structo gives you a fast and reliable
way to do it from your phone or tablet.