Molecular dynamics simulations and Hartree-Fock calculations, for crystalline material, predicted that configuration was remarkably stable. Energetic considerations implied that the hexa-vacancy did, in fact, form in real material. It was also expected to grow, rather than dissociate, during heat treatment. The energy eigen-values, and the charge distribution, implied that it gave rise to no electrical or optical activity. On the other hand, it constituted a large void in the crystal and could be an efficient gettering center and a precursor of extended defects.

S.K.Estreicher, J.L.Hastings, P.A.Fedders: Applied Physics Letters, 1997, 70[4], 432-4