Athanor by arbastro
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How to type atom labels like CO2Et or NHBoc

With the Text tool (T), click an atom, type its label and press Enter. Or point at the atom with any tool and press Enter. Elements and known groups such as CO2Et, NHBoc and OMe are read as atoms.

Steps

  1. Press T for the Text tool.

  2. Click the atom you want to label. A text box opens on it.

  3. Type the label, for example CO2Et.

    Typing CO2Et on the end of a bond attached to a benzene ring.Typing CO2Et on the end of a bond attached to a benzene ring.

  4. Press Enter. The atom becomes that group.

    The finished label: ethyl benzoate, drawn as benzene with a CO2Et label.The finished label: ethyl benzoate, drawn as benzene with a CO2Et label.

Without the Text tool

Point at the atom with any tool and press Enter, then type the label. For a single element, just press its letter instead, such as N or O. See How to change an atom to another element.

Labels that count as chemistry

An element symbol such as Cl or Br, and a group Athanor knows such as CO2Et, NHBoc, OMe or Ph, are read as atoms: the formula and molecular weight in Layers and Properties include them, and Object › Expand labels draws them out.

A label Athanor does not know is kept as you typed it but is not counted in the formula. Check Layers after typing a longer group, and draw it out with bonds if it is not counted. See How to use abbreviations like OMe, Boc and Ph.

Atoms, bonds and ringsHow to use abbreviations like OMe, Boc and PhPoint at an atom, press Enter and type a label such as OMe or Ph. Object › Expand labels draws a label out as its atoms; Object › Contract to label turns selected atoms back into a label; Define abbreviation… names a group as your own label.Drawing basicsHow to change an atom to another elementPoint at an atom and press its letter (C, N, O, S, P, F, I, H, B or K). For anything else, point and press Enter to type a label such as Cl, Br or OMe, or select atoms and choose an element in View › Periodic table.

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Last updated Nov 12, 2026