Molecular Structure Builder - Sketch Atoms & Bonds

2D STRUCTURE EDITORClick to select · Drag to move

Click canvas to place atoms · Use Draw bond, then click two atoms · Drag atoms to moveKeyboard: Delete · Arrows · Ctrl+Z

STRUCTURE INSIGHTS

Inspect & refine

Live chemistry checks and an illustrative 3D view.

3D preview

DRAG TO ROTATE · SCROLL TO ZOOM

3D viewing style

Illustrative only. Coordinates are generated from the 2D sketch, not energy-minimized. This is not a scientifically validated conformer.

Molecular properties

Checking

Molecular formula—

Molar mass (approx.)—

Atoms / bonds—

Components—

Selected atom / bond

Select an atom or a bond to adjust its properties.

SMILES representation

—

Noncanonical connectivity notation; aromaticity, stereochemistry, isotopes and chemically optimized geometry are not inferred.

Privacy-first chemistry sketching

No account or server processing. Validate structures and molecular interpretations with specialized cheminformatics software before scientific use.

Using Molecular Structure Builder

Start from a template or sketch supported atoms and bonds, then inspect the schematic and illustrative preview. Save editable JSON and review the stated limitations before using exported structure files elsewhere.

Formula and molar mass use simplified rules; 3D and XYZ coordinates are illustrative rather than computed conformers. Stereo, isotopes, radicals, aromatic SMILES and many metadata features are unsupported and rejected on import. Exports do not verify molecular identity or scientific accuracy.

Choose an editable sketch, structure exchange or illustrative view

Project JSON: preserve the supported editable atom/bond sketch.
MOL, SDF or simple SMILES: use the restricted exchange workflows and inspect import/export limitations.
SVG or PNG: share a labeled schematic or supported snapshot.
XYZ/3D: inspect illustrative coordinates rather than an energy-minimized molecular conformer.

Practice: inspect a small atom-bond sketch

Place two supported atoms and connect them with a supported bond.
Inspect the displayed labels, validation feedback and illustrative view.
Save JSON before a structure-format handoff, and review the destination's interpretation independently.

This is an authored sketching exercise, not a verified molecule, computed conformer or scientific result.

Molecular sketch questions

Do the formula, mass and 3D display establish molecular identity?

No. Formula and mass use simplified rules, and the coordinates are illustrative. Exports do not verify identity, geometry, stability or scientific accuracy.

Will any SMILES or MOL/SDF file import without information loss?

No. Stereo, isotopes, radicals, aromatic SMILES and many metadata features are unsupported and rejected. Keep original structure files and read rejection messages rather than assuming full format compatibility.