Oxides subhalides

See also Borates Boric acid Sodium borates boron oxides, 4 246-249 boron oxides table,4 242t environmental concerns, 4 284—285 health and safety factors, 4 285-288 occurrence, 4 245—246 Boron perchlorates, 18 278 Boron phosphate, 4 242t, 283 Boron removal, from water, 14 418 Boron-stabilized carbanions, 13 660-661 Boron subhalides, 4 141 Boron suboxide, 4 242t Boron tribromide, 4 138 manufacture, 4 145—146 physical properties of, 4 139-140t, 325 reactions, 4 141 specifications, 4 147t uses of, 4 149 Boron trichloride, 4 138 manufacture, 4 145—146 physical properties of, 4 139-140t reactions, 4 141... 

The easily available subhalide Gal (see above) has often been employed for the synthesis of unusual secondary products. Treatment with PEt3 yielded the trigallium derivative Ga3I5(PEt3)3 (131) in moderate yield, which contains a chain of three Ga atoms.28 Each Ga atom is coordinated by a triethylphosphane ligand, and the oxidation states are + 2 (terminal Ga atoms) and +1 (inner Ga atom). The Ga-Ga bond lengths (245.6 pm on average) are as expected. 

The colored subhalides of Ca, Sr, and Ba are now recognized as mixed-metal/metal dihalide phases. This section deals with the change of 0 to +2 oxidation state exclusively. 

Tellurium forms a series of subhalides, e.g. Te3Cl2 and Te2Cl, the structures of which can be related to the helical chains in elemental Te. When Te is oxidized to Te3Cl2, oxidation of one in three Te atoms occurs to give polymer 15.37. 

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