The gold centers exhibit square planar coordination with bond angles of roughly 90 degrees.

This coordination difference can be attributed to the Jahn-Teller effect but more so to the decrease in π-back bonding of the gold atoms with the bromine ligands compared to the π-back bonding found with fluorine and chlorine ligands.

It is also this decrease in π-back bonding which explains why gold tribromide is less stable than its trifluoride and trichloride counterparts.

[14] Another catalytic use of gold tribromide is in the nucleophilic substitution reaction of propargylic alcohols.

Acetaminophen, ascorbic acid, heroin, lactose, mannitol, morphine, and sucrose all cause an instant colour change to purple, as do other compounds with phenol and hydroxyl groups.

The cause for the change of color from purple to dark blackish-purple is unknown; however, it may be due to a redox reaction that produces a small amount of colloidal gold.