Chemical Structure Editors - STEM - Free and Open Access Resources for Research - LibGuides at University of California San Diego

If you don't have access to ChemDraw, there are free and low-cost options for drawing chemical structures and reactions

MarvinSketch & MarvinView
Free structure/reaction drawing editor from ChemAxon. Structure editor supporting multiple file formats, for Windows, Mac and Linux. Marvin JS is one of the editor options in Reaxys, along with ChemDraw JS.

Free access is for personal, non-commercial use only. Prompted to renew every 2 months. Registration required. Under your account info, you'll find a alphanumeric license key and an offline license for downloading. You can use either option to activate your Marvin license once installed.
BIOVIA Draw (no-fee version)
Chemical structure drawing tool. No-fee option for academic and non-commercial use, but registration required to download. Formerly Accelrys (ISIS/Draw).
ChemDoodle
Structure/reaction editor for Windows, Mac and Linux. Includes ChemDoodle 2D, 3D, and Mobile. Several pricing options, with a free trial available.
ChemDraw Direct (ChemDraw JS)
Web-based "lite" version of ChemDraw. To enable copy/paste, click the grey clipboard in the lower left of the window and follow the instructions.