1.4 Tetrahedral Geometry

Here's a 3-dimensional representation of a molecule of methane. You can use the mouse to rotate the model around and see it from all sides. This is a ball-and-stick model, the oldest way to show the structure of a molecule, and still one of the most accurate.

The carbon atom in the center is bonded to four hydrogen atoms, satisfying not only the carbon's valence but also the hydrogens' valences. Methane's formula is CH₄, representing the single carbon atom (C) and the four hydrogens (H). It is the simplest hydrocarbon, a compound of only hydrogen and carbon.

We can see that the hydrogen atoms are spaced equidistantly; they are all as far apart as physically possible while staying their optimum distance from the carbon atom. They form the shape of a tetrahedron, with an angle of about 109° between any two hydrogen atoms. Carbon is a tetrahedral element; its bonds will generally attempt to maintain this 109° angle in all compounds.

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