Interstitial Sites in the Face-Centered Cubic Lattice

2 Interstitial Sites in the Face-Centered Cubic Lattice 

The size of the tetrahedral interstitial site in the fee structure can be shown to be 

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Reaction with methane at 2,100°C produces hafnium carbide, a dark-gray, brittle solid, which is not a true stoichiometric compound. It probably is a homogeneous mixture in which carbon impregnates interstitial sites in the face-centered cubic lattice of hafnium. 

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