In a tetrahedral molecular geometry, a central atom is located at the center with four substituents that are located at the corners of a tetrahedron. The bond angles are cos^-1(-1/3) =109.4712206...° ˜ 109.5° when all four substituents are the same, as in methane (CH₄). The perfectly symmetrical tetrahedron belongs to point group T_d, but most tetrahedral molecules are have lower symmetry. Tetrahedral molecules can be chiral.