# Tetrahedral hard sphere model

The **tetrahedral hard sphere model** consists of four hard spheres located on the vertices of a regular tetrahedron.

## Second virial coefficient[edit]

The second virial coefficient is given by (^{[1]} Eq.5):

where is the reduced elongation, is the corresponding reduced volume, and .

## Equation of state[edit]

The equation of state is given by (^{[1]} Eq. 17):

where , , , and .