MoleculeSketch

MoleculeSketch is a simple and easy to use drawing App for chemical formulas and reactions.

It has following features:
+ add atoms and bonds nicely by position locking (can be disabled)
+ choose different double bond styles
+ add stereo bonds
+ show missing hydrogen atoms depending on free valences
+ show non bonding electron pairs on heteroatoms
+ change background color of drawing area
+ copy/paste/cut molecules and drawings
+ past drawings into other applications as pdf drawing
+ use trackpad gestures for zooming and rotation
+ access drawing attributes from popover panels
+ add reaction arrows and text fields
+ calculate average mass and formula of molecules