Аннотация:A new protic ionic liquid (Tс = 14±1 °C) – pyridinium hydrogen dinitrate – was obtained at room temperature from a solution of pyridinium nitrate in anhydrous nitric acid in a desiccator over P2O5. Single crystal X-ray diffraction study revealed that the solid state structure of [(PyH)2(NO3)][H2(NO3)3] consists of hydrogen bonded cations [(PyH)2(NO3)]+ and anions [(NO3)(HNO3)2]- with a previously unknown configuration, containing two HNO3 molecules linked via hydrogen bonds to the central NO3-anion by sin-anti type.