Britannica Sources used in this answer

How does the structure of methane relate to its tetrahedral shape?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

representations of molecular structure — molecule Several methods of representing a molecule's structure. In Lewis structures, element symbols represent atoms, and dots represent electrons surrounding them. A pair of shared electrons (covalent bond) may also be shown as a single dash. The ball-and-stick model better illustrates the spatial arrangement of the atoms. For aromatic compounds, the Kekulé structure is common, in which each bond is represented by a dash, carbon atoms are implied where two or more lines meet, and hydrogen atoms are usually omitted. Bond-line formulas, similar to the Kekulé structure, are often used for complex nonaromatic organic compounds. Sugars are often drawn as Fischer projections, in which the carbon “backbone” is drawn as a straight vertical line, with carbon atoms implied where horizontal lines intersect the vertical one.

The tetrahedral shape of the methane molecule (CH₄) is a direct result of how its electron pairs and atomic orbitals are arranged to minimize repulsion and achieve stability.

According to VSEPR theory, the carbon atom in methane is surrounded by four bonding electron pairs. Because these negatively charged pairs repel one another, they maximize their separation by adopting a tetrahedral disposition, with the carbon atom at the center and hydrogen atoms at the four corners. This arrangement results in a bond angle of 109.5°.12

From the perspective of valence bond theory, this geometry is explained by hybridization. The carbon atom mixes its 2s and three 2p orbitals to create four equivalent sp³ hybrid orbitals. These orbitals are oriented toward the corners of a regular tetrahedron, allowing each to form an identical sigma bond with a hydrogen atom.3