| has gloss | eng: There are three sets of gallium halides, the trihalides where gallium has oxidation state +3, the intermediate halides containing gallium in oxidation states +1, +2 and +3 and some unstable monohalides, where gallium has oxidation state +1. Trihalides All four trihalides are known. They all contain gallium in the +3 oxidation state. Their proper names are gallium(III) fluoride, gallium(III) chloride, gallium(III) bromide and gallium(III) iodide. ;GaF3 :GaF3 is a white solid which sublimes before it melts, with an estimated melting point above 1000oC. It contains 6 co-ordinate gallium atoms with a three-dimensional network of GaF6 octahedra sharing common corners. ;GaCl3, GaBr3 and GaI3 :These all have lower melting points than GaF3, (GaCl3 mp 78 °C, GaBr3 mp 122 °C, GaI3 mp 212 °C) reflecting the fact that their structures all contain dimers with 4 coordinate gallium atoms and 2 bridging halogen atoms. They are all Lewis acids, forming mainly 4 co-ordinate adducts. GaCl3 is the most commonly used trihalide. |
