Nickel is a metal in group VIII of the periodic table ... At room temperature the crystal structure is face-centered-cubic with a basis of one Ni atom. The fcc unit cell is illustrated.

IT has been shown by one of us 1 that, at ordinary temperatures, the structure of nickel oxide is slightly deformed from face-centred cubic symmetry. Later work 2 proved that at − 180° C.

RECENTLY 1 it has been suggested that interstitial hydrogen in a face-centred cubic lattice will produce embrittlement and cause delayed failure under the appropriate conditions. Basically ...