Experimental and Theoretical Study of 1,5‐Diamino‐4‐H‐1,2,3,4‐Tetrazolium Perchlorate

The synthesis and characterization of 1,5‐diamino‐1,2,3,4‐tetrazolium perchlorate were carried out. Experimental evidence strongly supports the protonation of a nitrogen atom of the tetrazole ring, including the structure observed in a single crystal X‐ray diffraction study of the title compound. Quantum chemical calculations were performed at the CCSD(T)/6‐311G(2df, p)//MP2/6‐311G(d, p) level of theory to determine the relative energies of all possible N‐protonated structures of the 1,5‐diamino‐1,2,3,4‐tetrazole ring. The predicted geometry of the most stable isomer compares favorably with the experimentally observed structure.