Structure in the electrically detected magnetic resonance signal from a common type of Si diode has been resolved and measured for different orientations of the magnetic field in the (111) plane. The center is found to haveC3vsymmetry with &Dgr;g∥≳0 and &Dgr;g⊥≊0. It is proposed that the signal is due to a broken bond, or combination of colinear broken bonds, in a vacancy cluster which acts as a recombination center. The most likely cluster is the divacancy which has captured an electron in the antibonding state formed from the most distant broken bonds and a hole in a bonding state associated with the divacancy. ©1995 American Institute of Physics.