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Arrows and Mechanisms
This page explains how to add editable reaction arrows, electron-pushing arrows, charge marks, brackets, and labels to a chemical scheme.
ChemDraft keeps scheme marks as document objects, so they can be selected, moved, saved, and exported with the rest of the drawing. Arrows are not merely a picture laid over a molecule.
Caption: A reaction scheme can combine structures, an editable arrow, and text labels on one page.
Open the Arrows Toolbar and choose an arrow tool, then click to place a default-length arrow or drag from its tail to its head. The toolbar includes these named choices:
| Tool | Use |
|---|---|
| Reaction Arrow | A normal forward reaction arrow |
| Reaction Arrow (Large Head) | A forward arrow with a larger head |
| Dashed Reaction Arrow | A dashed forward arrow |
| Resonance Arrow | A two-headed arrow |
| Equilibrium Arrow | Opposed, parallel half-shafts |
| Retrosynthesis Arrow | A parallel-shaft retrosynthetic arrow |
| No-Reaction Arrow | A forward arrow crossed at its shaft |
These are art arrows with handles: select one to move it, change endpoints, bend an applicable line into an arc, and adjust an arrowhead. Right-click an arrow and choose Set as Default Arrow Style to reuse its visual treatment for that arrow tool across restarts. That records the reusable appearance—such as stroke, dash, head sizes, and curve—not its location or length.
Imported CDXML arrows in the reaction, resonance, equilibrium, and retrosynthesis families return as the same editable art-arrow form. The familiar arrow types are therefore practical drawing objects, not a one-way import result. See CDXML Support for compatibility details.
For a mechanism, use Electron Pair Push Arrow for a full-headed arrow or Radical Push Arrow for a half-headed fishhook. These tools make mechanism-arrow objects that attach to an atom or charge mark. Their Bézier control handles shape the curve; the attachment stays meaningful when the associated molecule is moved, rotated, scaled, or flipped.
Use the charge/electron-mark palette for circled and plain charge marks, radical cation and radical anion marks, a plain radical, and a lone-pair mark. A charge mark is movable and associated by proximity to its atom. Adding plus or minus to an existing mark changes its magnitude rather than drawing overlapping symbols; a mark is removed when its charge returns to zero.
Electron arrows and charge marks communicate a proposed electron-flow interpretation. They do not infer a reaction, balance an equation, or alter the molecular connectivity for you. Draw the structures and conditions you intend to show, then use these annotations to explain the step.
The bracket tool creates editable brackets. Use brackets to group a polymer repeat, indicate a region of a scheme, or frame related material. Add conditions, reagents, yields, captions, or ring labels with text objects. Formula text can use subscript and superscript spans, which is useful for a reagent or charge annotation.
For a clean scheme, place reactants and products first, align their visual centers, then draw the arrow through the open space between them. Put conditions above or below the shaft rather than on it. Keep explanatory text separate from molecular labels: this preserves clear selection and makes later revision much easier.
Use Edit › Copy As or the object right-click menu’s Copy As flyout to copy a selection or, if nothing is selected, the page. Available forms include SMILES, InChI, InChI Key, CDXML Text, MOL Text, MOL V2000 Text, SVG, and PNG. When a molecule is selected, its anchored charge marks and mechanism arrows are included with it in SVG and PNG copies.
Choose SVG when the destination accepts vector graphics; choose PNG for a fixed raster image. For exchangeable chemical data rather than a figure, use CDXML or MOL text and review any reported conversion warnings. Copy, Paste, and Clipboard explains the clipboard formats more broadly.