The systems phosphine-boron trifluoride, arsine-boron trifluoride and hydrogen bromideboron trifluoride were investigated. Immiscibility of the liquid components was encountered in certain regions of the arsine-boron trifluoride and the hydrogen bromide-boron trifluoride systems. No evidence was found for compound formation between arsine and boron trifluoride, nor between hydrogen bromide and boron trifluoride. However, there is evidence that two coordination compounds exist between phosphine and boron trifluoride in the solid state, namely, PHyBF3 and PH3.(BF3)2.It is postulated that the arsenic atom in arsine is too large to approach sufficiently close to the boron atom of boron trifluoride to coordinate, al-though the tendency for these atoms to coordinate is sufficiently great. It is calculated that less steric hindrance is encountered with boron trichloride than with boron trifluoride. This postulate explains the fact that arsine coordinates with boron tribromide and boron trichloride, but not with boron trifluoride.It is believed that the ionic character of the hydrogen-halogen bond of the hydrogen halides is the controlling factor in the formation of coordination compounds between the hydrogen halides and boron trifluoride, accounting for the fact that the more ionic hydrogen fluoride forms three coordination compounds, whereas hydrogen chloride and hydrogen bromide form none.

No abstract

No abstract

No abstract

No abstract