Chemical preparation, X-ray single crystal, thermal behaviour, and IR spectroscopic studies on a new organic compound, the bis (tertbutylamonium) dihydrogendiphosphate denoted TBAP, are described. The TBAP crystallizes in the monoclinic system with C2/c space group. The unit cell dimensions are a=19.840(7)Å, b=8.932(4) Å, c=12.518(5)Å, ï¢=136.81(2)Å, with V=1518.3(11) Å and Z= 4. The structure has been solved by a direct method and refined to a reliability R factor of 0.0444 using 1649 independent reflections. The central oxygen atomof the H2P2O7 group is located on a twofold axis providing a binary internal symmetry of the phosphoric entity. Two kinds of hydrogen bonds coexist in the structure. The mineral anions, linked by the first one O-HÂ O, built chains running parallel to the c axis. The organic cations, assemble these chains by the second one N-HÂ O to perform a three dimensional network.