Holes bordered by heteroatoms within the diamond lattice

Holes bordered by heteroatoms within the diamond lattice 

If a carbon atom in the diamond lattice is deleted and if the four carbon atoms to which it had been connected are replaced by nitrogen heteroatoms, a tetrahedral hole results [21]. In principle, a small metal cation or a proton may become trapped in the hole (Fig. 6). When a similar process is performed for a pair of adjacent carbon atoms, the result is a quasi-octahedral hole bordered by six nitrogen heteroatoms it too may include a metal cation in Fig. 7 a portion of the diamond lattice with several such holes is presented. 

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