BKChem for Mac

Quick summary

BKChem is a vector-based drawing app for macOS focused on manually composing chemical structures. It provides an intuitive interface for building molecules bond by bond, with controls that enforce specific bond lengths and angles. The tool also supports linear formulas and the placement of charges and radical markers to streamline structure creation.

Drawing features and workflow

Precise bond-by-bond construction with constraints on angle and length to keep geometry consistent.
Easy editing tools that let you adjust individual bonds and atoms without rebuilding whole fragments.
Support for annotating structures with formal charges and unpaired electrons (radicals).
Output is vector-native, so drawings remain sharp at any scale and are suitable for publication or presentations.

Ready-made structure templates

Cycloheptane (seven-membered saturated ring)
Cyclopentane (five-membered saturated ring)
Cyclopentadiene (five-membered ring with conjugated double bonds)
Purine (bicyclic heterocycle common in nucleotides)
Benzene (aromatic six-membered ring)

Encapsulated PostScript (EPS)
SMILES strings for compact textual representation
MDL Molfile (Molfiles) for cheminformatics interchange
CML version 2 (Chemical Markup Language v2)
CML (Chemical Markup Language)
PNG raster images for easy web use
PDF documents for printing and distribution
OpenDocument Drawing (ODF) / OpenOffice Draw compatibility
SVG vector graphics for web and design tools

Quick note on learning resources

If you prefer guided walkthroughs or video tutorials, check YouTube — many creators post free demonstrations and how-tos for BKChem and similar chemistry drawing tools.