Draw your first molecule
Draw ethanol
Section titled “Draw ethanol”ReShiki opens with a blank canvas.
- Press 1 for a single bond. Choose New first if a drawing is already open.
- Drag a bond. Drag from its endpoint to add a second bond.
- Select the last atom and press o. Its label becomes OH.
- Click empty space to clear the selection, then Check. Ethanol should read C2H6O.
Press ⌘S on Mac or Ctrl+S elsewhere to save an editable .rsk file. ⌘/Ctrl+Z undoes an edit.
Molecular properties follows the selected atoms and bonds automatically. With nothing selected, it shows the Whole drawing. A partial selection is treated as a separate fragment, with implicit hydrogens recalculated at cut bonds. Selecting only artwork shows no molecular values. Copy SMILES uses the same scope as the displayed properties.
The Examples menu under Import inserts into the existing drawing. Each inserted molecule stays selected: drag it to position it, or use Delete or Undo to remove it.
Choose an element
Section titled “Choose an element”Click C in the toolbar to reuse the current element. Hold the button or click its lower-right triangle to choose another element, then click an atom to replace it or empty space to place it.
To add the chosen element with a new bond, drag from an existing atom. Clicking an existing atom still replaces it. Hold Option/Alt while dragging to bypass length and angle constraints. Dragging onto another existing atom connects them without changing their elements.
For common labels, hover an atom and press c, n, o, s, p, f, or h (lowercase). ReShiki adds the appropriate hydrogen count.
Change a bond
Section titled “Change a bond”Click Single, Double, or Triple to select a bond immediately. Click Other bonds for wedges, dashed bonds, and the remaining styles. Choose a style, then draw or click an existing bond.
| With a bond selected or hovered | Press |
|---|---|
| Single / double / triple | 1 / 2 / 3 |
| Move a double bond’s second line | 2 again |
| Erase an object | Choose the eraser, then click or drag |
The controls above the canvas set Length and Angles. Hold Alt/Option while dragging to draw freely.
The eraser deletes atoms, bonds, labels, arrows, and artwork along the full drag path. One undo restores the entire stroke.
Add a ring or chain
Section titled “Add a ring or chain”Click the ring tool to use the last chosen ring; it starts with a six-membered ring. Hold the button briefly or click its lower-right triangle to choose a ring, benzene, or a chair projection. Click empty space or an existing atom/bond to place it.
Drag on empty space to rotate the ring as you place it: its first atom stays where you pressed and its first bond turns toward the pointer in 15° steps. Dragging from an atom aims the ring in the same steps. Hold Option/Alt while dragging to rotate freely; the ring keeps its size either way.
Straight and snaking chains have separate one-click toolbar buttons. Shift+x (uppercase X) selects a straight chain when no atom or bond is targeted. Choose the snaking-chain button for a snaking chain. Drag to set its length. Straight chain can use an exact atom count; Snaking chain has a Max atoms limit.
Use Shift+R to switch saturated/aromatic ring drawing while keeping the member count. With Select and a complete 3–8 member ring selected, the same shortcut converts that ring in place. This changes drawing notation without inferring charges. Select an already aromatic ring and press Cmd/Ctrl+Alt+K (or Alt+K on Windows) to switch between a circle and alternating bonds.
For a partial delocalization curve, select consecutive ring atoms and right-click → Bond appearance… → Toggle inner ring curve, or use Properties → Bond appearance. Select the whole ring for a circle. Bond orders stay unchanged; keep .rsk or use figure export for this depiction.
Choose Benzene for alternating bonds, or Aromatic circle for the circle form. Hold Cmd/Ctrl while placing a ring to use the circle form for that placement. For an existing aromatic ring, select the complete ring, move the pointer off atoms and bonds, and press lowercase a to toggle its display. Chairs and Haworth projections retain their geometry when the modifier is held. See the complete shortcuts and editable examples.