– Ni 6 (octahedral) : As 6 (trigonal prismatic)
As with Ni in all Oh holes
Polyhedra – face-sharing , edge-sharing
(a) The nickel-arsenide structure; (b) and (c) show the six-fold coordination geometries of As (trigonal prismatic) and Ni (octahedral), respectively, and (d) is the projection representation of the unit cell. The short M–M interaction is shown as a dotted line in (c).
Related Structure: Rocksalt (NaCl)