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The lacunar pattern of this grain therefore includes six tetragonal and nine hexagonal faces. Relating this to polyhedrons, we find that no pentakaidecahedron with such a combination of faces can exist (see page 199). If, however, the two polar areas be regarded as filled-in hexagonal lacunae, making 17 lacunae in all, the pattern corresponds to a heptakaidecahedron with 6 tetragonal and 11 hexagonal faces, which appears to be the proper interpretation of this pattern.
Source: wiktionary
The host lattice consists of 156 water molecules per unit cell, which form 16 identical heptakaidecahedra (17-hedra) and 12 identical octahedra (8-hedra) in a face sharing arrangement with cubic symmetry.
Source: wiktionary
Other clathrates are the Brâ‚‚ hydrate with a pentakaidecahedral cage of water molecules or the tert-butylamine hydrate with a heptakaidecahedron cage of water molecules.
Source: wiktionary
Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.