What is octahedra?

Some articles on octahedra:

Compound Of Twenty Octahedra With Rotational Freedom
... polyhedron compound is a symmetric arrangement of 20 octahedra, considered as triangular antiprisms ... It can be constructed by superimposing two copies of the compound of 10 octahedra UC16, and for each resulting pair of octahedra, rotating each octahedron in the pair by an ... When θ is zero or 60 degrees, the octahedra coincide in pairs yielding (two superimposed copies of) the compounds of ten octahedra UC16 and UC15 ...
Compound Of Twenty Octahedra
... This uniform polyhedron compound is a symmetric arrangement of 20 octahedra (considered as triangular antiprisms) ... It is a special case of the compound of 20 octahedra with rotational freedom, in which pairs of octahedral vertices coincide ...
Molybdenum Trioxide - Structure
... state, anhydrous MoO3 is composed of layers of distorted MoO6 octahedra in an orthorhombic crystal ... The octahedra share edges and form chains which are cross-linked by oxygen atoms to form layers ... The octahedra have one short molydenum-oxygen bond to a non-bridging oxygen ...
Tetrahedral-octahedral Honeycomb
... It is composed of alternating octahedra and tetrahedra in a ratio of 12 ... It is vertex-transitive with 8 tetrahedra and 6 octahedra around each vertex ... It is edge-transitive with 2 tetrahedra and 2 octahedra alternating on each edge ...
Bitruncated Cubic Honeycomb
... tessellation (or honeycomb) in Euclidean 3-space made up of truncated octahedra ... It has 4 truncated octahedra around each vertex ... Being composed entirely of truncated octahedra, it is cell-transitive ...