Some molecules, such as XeF or , have a lone pair that distorts the symmetry of the molecule from O to C. The specific geometry is known as a monocapped octahedron, since it is derived from the octahedron by placing the lone pair over the centre of one triangular face of the octahedron as a "cap" (and shifting the positions of the other six atoms to accommodate it). These both represent a divergence from the geometry predicted by VSEPR, which for AXE predicts a pentagonal pyramidal shape.