In Repeating group dialog you can create a Repeating unit, an SRU polymer or a Link node; or you can change the repeat pattern and the label of these substructural groups.

Repeat pattern values

• (ht) - head-to-tail (not displayed on the canvas)

• hh - head-to-head

• eu - either/unknown

Label values

• number (e.g. 3)

• range (e.g. 5-8)

• lowercase letters (a-z except:c and f)