Tetrahedron generally known as triangular pyramid consists of 4 triangular faces, 6 edges and 4 vertices. The base of the tetrahedron is a triangle. All the vertices have the same atom that is bonded to the central metal atom which lies in the centre of the tetrahedron. We take [tex][SiO_4]^4^-[/tex] as an example to see how the atoms actually bond in tetrahedron. It is quite visible from the image that 4 O-atoms lies on all the 4 vertices and 1 Si-atom lie in the centre.
