If a molecule has six electron domains, what is its hybridization type?

When a molecule has six electron domains, it indicates that there are six regions of electron density around the central atom. These regions can be made up of single bonds, double bonds, triple bonds, or lone pairs. The hybridization type is determined by the geometry that these electron domains adopt.

For six electron domains, the corresponding molecular geometry is octahedral. To accommodate this geometry, the atomic orbitals hybridize into six equivalent sp3d2 hybrid orbitals. This sp3d2 hybridization involves the mixing of one s orbital, three p orbitals, and two d orbitals from the central atom.

The resulting orbital set allows the molecule to adopt the octahedral arrangement, where the electron domains are positioned at the corners of an octahedron, maximizing their distance from one another to minimize electron-electron repulsion.

Other hybridization types mentioned do not fit the arrangement of six electron domains; for example, sp3d corresponds to five electron domains (trigonal bipyramidal geometry), and sp3 is appropriate for four electron domains (tetrahedral geometry) or sp2 for three electron domains (trigonal planar). Therefore, sp3d2 is the correct choice for a molecule with six electron domains.