Cage structures for polyborate ions.
Conventional concepts of chemical bonding appear inadequate to explain the structures of the anhydrous polyborates. A cage-type structure with occluded oxide ion is proposed for the octaborate, hexaborate, and tetraborate ions. The proposed structure is discussed in terms of the composition, x-ray diffraction patterns, and nuclear magnetic resonance spectra of the sodium polyborates.
Dunicz
B L
BL