In chemistry, the capped octahedral molecular geometry describes the shape of compounds where seven atoms or groups of atoms or ligands are arranged around a central atom defining the vertices of a

gyroelongated triangular pyramid In geometry, a Johnson solid is a strictly convex polyhedron each face of which is a regular polygon. There is no requirement that each face must be the same polygon, or that the same polygons join around each vertex. An example of a Johnson ...

. This shape has C_3v symmetry and is one of the three common shapes for heptacoordinate transition metal complexes, along with the

pentagonal bipyramid In geometry, the pentagonal bipyramid (or dipyramid) is third of the infinite set of face-transitive bipyramids, and the 13th Johnson solid (). Each bipyramid is the dual of a uniform prism. Although it is face-transitive, it is not a Platoni ...

and the capped trigonal prism. Examples of the capped octahedral molecular geometry are the heptafluoromolybdate () and the heptafluorotungstate () ions. The " distorted octahedral geometry" exhibited by some AX₆E₁ molecules such as

xenon hexafluoride Xenon hexafluoride is a noble gas compound with the formula XeF6. It is one of the three binary fluorides of xenon, the other two being XeF2 and XeF4. All known are exergonic and stable at normal temperatures. XeF6 is the strongest fluorinat ...

(XeF₆) is a variant of this geometry, with the lone pair occupying the "cap" position.

References

Stereochemistry Molecular geometry {{chemistry-stub