Crystal structure and vibrational spectra of piperazinium bis(4-hydroxybenzenesulphonate) molecular–ionic crystal

The piperazinium bis(4-hydroxybenzenesulphonate) crystallizes from water solution at room temperature in P21/c space group of monoclinic system. The crystals are built up of doubly protonated piperazinium cations and ionized 4-hydroxybenzenesulphonate anions that interact through weak hydrogen bonds of O–H⋯O and N–H⋯O type. Mutual orientation of anions is determined by non-conventional hydrogen bonds of C–H⋯π type. Room temperature powder FT IR and FT Raman measurements were carried out. The vibrational spectra are in full agreement with the structure obtained from X-ray crystallography. The big single crystals of the title salt can be grown.