Alkyl-chain disorder in tetra­isohexyl­ammonium bromide

Tetra­isohexyl­ammonium bromide [systematic name: tetra­kis­(4-methyl­pentyl)aza­nium bromide], C₂₄H₅₂N⁺·Br^-, is a power­ful structure II clathrate hydrate crystal-growth inhibitor. The crystal structure, in the space group P3₂21, contains one ammonium cation and one bromide anion in the asymmetric unit, both on general positions. At 100 K, the ammonium cation exhibits one ordered isohexyl chain and three disordered isohexyl chains. At 250 K, all four isohexyl chains are disordered. In an effort to reduce the disorder in the alkyl chains, the crystal was thermally cycled, but the disorder remained, indicating that it is dynamic in nature.