- Type I: A2B6X46, cages: small AX12 (dodecahedron) and large BX14 (hexagonal truncated trapezohedron), examples: Na2K6Si46, CO2 or CH4 in water ice cage.
- Type II: A4B2X34, cages: small AX12 (dodecahedron) and large BX16 (51264), examples: Na4K2Si34, O2 or N2 in water ice cage.
Relation to foams:
- Weaire-Phelan structure corresponds to Type I clathrate.
- Kelvin structure corresponds to hypothetical NaSi6 clathrate which in fact does not exist because of high angle and steric strains.