  Atomistic origin of stacking faults in non-close packed systems is a
fundamentally distinct mechanism from the well-known close packed structures
with ABC stacking, and represents an uncharted territory in material research.
According to experimental data, stacking faults in simple hexagonal WC happen
in {1-100} planes that are packed rectangularly and have ABAB stacking. This
work identified the type of the defect and crystallographic behaviour by
creating energetically relaxed potential atomistic models of stacking faults in
WC. Experimental evidence supporting the rotation axis along stacking fault
caused by variation in carbon ordering at the interstitial site has been
established, in accordance with the theoretical model.
