title: Tetra-methyl-ammonium hemi(terephthalate) dihydrate.
abstract: In the title compound, (CH(3))(4)N(+)·0.5C(8)H(4)O(4) (2-)·2H(2)O, the complete terephthalate dianion is completed by twofold symmetry and has a dihedral angle of 23.5 (2)° between the carboxyl-ate group and its parent ring. Two independent water mol-ecules serve as both donors and acceptor in the construction of undulating hydrogen-bonded host layers with various O-H⋯O contacts ocurring between the anion and two water mol-ecules. At the same time, the tetra-methyl-ammonium cations, as the sphere-like guest species, are arranged in two rows between neighboring host layers, with an approximate inter-layer distance of 7.36 Å, forming a sandwich-like crystal structure.
authors.affiliation: Key Laboratory of Polymer Materials of Gansu Province, Ministry of Education, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, Gansu, People's Republic of China.
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Yang
authors.forename: Laipeng
authors.initials: L
authors.lastname: Shi