Athanor by arbastro
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How to add rings

Press R, then J for benzene or 3 to 8 for that ring size, and click empty canvas. Click a bond of another ring to fuse onto it, or an atom to make a spiro ring. Insert › Ring size takes any size from 3 to 30.

Steps

  1. Press R for the Ring tool. The row above the toolbar shows the ring templates, with benzene first.

    The Ring tool's templates: benzene, other ring sizes, chair and the projection templates.The Ring tool's templates: benzene, other ring sizes, chair and the projection templates.

  2. Pick a ring: J for benzene, or 3 to 8 for cyclopropane to cyclooctane.

  3. Click an empty spot on the canvas to place the ring.

  4. To fuse a ring, click a bond of a ring already on the canvas. The new ring shares that bond. Clicking a benzene bond with benzene makes naphthalene.

    A second benzene ring fused onto a bond of the first, making naphthalene.A second benzene ring fused onto a bond of the first, making naphthalene.

  5. To make a spiro ring, which shares a single atom, click an atom instead of a bond.

Placing benzene, then fusing a second benzene ring onto one of its bonds.

Any ring size

  1. Choose Insert › Ring size in the Main menu.
  2. Type the number of atoms in Ring atoms, from 3 to 30, for example 12 for a macrocycle. Tick Alternating double bonds for a ring with alternating single and double bonds.
  3. Click on the canvas to place it.

Ring size set to 12, above the Ring tool's templates.Ring size set to 12, above the Ring tool's templates.

With the keyboard

Point at a bond and press 4 to 8 to fuse a ring of that size onto it, or A for benzene. This works with any tool.

Drawing basicsHow to insert a structure by name, SMILES or CAS numberPress / (Quick insert), type a name such as caffeine, a SMILES string or a CAS number, and press Enter. The structure lands on the canvas, ready to edit.Keyboard shortcutsKeyboard shortcutsPress ? in a document for the Controls cheat sheet, or Ctrl+K and search for a command to see its shortcut. Every shortcut can be changed in Settings › Shortcuts. On a Mac, Ctrl is Cmd.

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Last updated Nov 12, 2026