ðə ɡˈɑː bˌiːˈɑːɹ θɹˈiː mˈɑːnoʊmɚ hɐz tɹˈɪɡənəl plˈeɪnɚ dʒiˈɑːmətɹi, bˌʌt wɛn ɪt fˈɔːɹmz ðə dˈaɪmɚ ɡˈɑː tˈuː bˌiːˈɑːɹ sˈɪks ðə dʒiˈɑːmətɹi ɚɹˈaʊnd ðə ɡˈæliəm sˈɛntɚ dɪstˈɔːɹts tə bɪkˌʌm ɹˈʌfli tˌɛtɹɐhˈiːdɹəl.
The GaBr3 monomer has trigonal planar geometry, but when it forms the dimer Ga2Br6 the geometry around the gallium center distorts to become roughly tetrahedral.