Knowledge Bank

The structures of $AsF3$ and $AsF5$ have been determined by the sector-microphotometer method of gas-phase electron diffraction. Observed parameters for $AsF2$ were distance As---F $1.707\pm 0.002\backslash AA$, angle F---As---F $96.1\pm 0.2dG$. The $AsF5$ molecule was found to be a trigonal bipyramid with an average As---F bond length of $1.678\pm 0.002\backslash AA$ and a difference between the As---$Faxial$ and As---$Fequatorial$ bonds of $0.026\pm 0.008\backslash AA$. Root-mean-square amplitudes of vibration have been determined.