The Structure of Tetrabutylammonium Bromide Hydrate (C4H9)4NBr·21/3H2O

Abstract

The results of the investigation using single crystal X-Ray diffraction analysis of tetrabutylammonium bromide hydrate structure (C₄H₉)₄NBr·2¹/₃H₂O, which was discovered in the tetrabutylammonium bromide–water binary system within the range of concentrated solutions, are presented in this communication. The (C₄H₉)₄NBr·2¹/₃H₂O compound is crystallized in the trigonal space group R3c, a=16.609(1) Å, c=38.853(2) Å. The structure is a packing of tetrabutylammonium cations and clusters composed of hydrogen-bonded water molecules and bromide anions. The change of water functions is discussed within one binary system tetrabutylammonium bromide–water. In the clathrate formation region water plays the role of the host, forming the water–anion host framework in clathrate polyhydrates, while in the region of concentrated solutions, in the case of (C₄H₉)₄NBr·2¹/₃H₂O compound, water functions as a guest, forming water-anion guest particle.