octahedron

Examples of octahedron in the following topics:

• Octahedral Complexes

  • Octahedral complexes have six ligands symmetrically arranged around a central atom, defining the vertices of an octahedron.
  • The octahedron has eight faces, hence the prefix octa-.

• Boranes: Boron-Hydrogen Compounds

  • ., B5H9 an octahedron missing one vertex)
  • arachno- (from the Greek for "spiders web") B occupies n vertices of an n+2 deltahedron (e.g., B4H10 an octahedron missing two vertices)
  • hypho- (from the Greek for "net") B occupies n vertices of an n+3 deltahedron (e.g., possibly B8H16 has this structure, an octahedron missing three vertices)

• Crystal Field Theory

  • For example, in the case of an octahedron, the t2g set becomes lower in energy.

• Tetrahedral and Square Planar Complexes

  • The removal of a pair of ligands from the z-axis of an octahedron leaves four ligands in the x-y plane.

• Applying the VSEPR Model

  • In an AX6 molecule, six electron pairs will try to point toward the corners of an octahedron (two square-based pyramids joined base-to-base).
  • In an octahedral molecule, six electron pairs will try to point toward the corners of an octahedron.

• Isomers in Coordination Compounds

  • When three identical ligands occupy one face of an octahedron, the isomer is said to be facial, or fac.

• Molecular Geometries

  • The bond angles are all 90°, and just as four electron pairs experience minimum repulsion when they are directed toward the corners of a tetrahedron, six electron pairs try to point toward the corners of an octahedron.

• Ionic Crystals

  • The answer is that each of those six chloride ions sits at the center of its own octahedron, whose vertices are defined by six neighboring sodium ions.