The structure of nido-Se2B9H9 has been determined unambiguously to be
the 7,9-isomer by ultra high-field (192.48 MHz) B-11 NMR spectroscopy.
The He(I) PE spectrum of 7,9-Se2B9H9 is compared with the results of
an MNDO MO calculation of the dithiaborane analogue 7,9-S2B9H9.