Preparation and Structure of Melemium Melem Perchlorate HC6N7(NH2)3ClO4·C6N7(NH2)3

A new perchlorate salt of melem (2,6,10‐triamino‐s‐heptazine, C₆N₇(NH₂)₃) was obtained from an aqueous solution of HClO₄ at lower concentration than the ones reported for the synthesis of melemium perchlorate monohydrate (HC₆N₇(NH₂)₃)ClO₄·H₂O. The new salt was identified as melemium melem perchlorate (HC₆N₇(NH₂)₃)ClO₄·C₆N₇(NH₂)₃ representing a melem adduct of water free melemium perchlorate. The crystal structure was solved by single‐crystal X‐ray methods ( , no. 2, Z = 2, a = 892.1(2), b = 992.7(2), c = 1201.5(2) pm, α = 112.30(3), β = 96.96(3), γ = 95.38(3)°, V = 965.8(4)·10⁶ pm³, 4340 data, 387 parameters, R1 = 0.039). Melemium melem perchlorate crystallizes in a layer‐like structure containing both protonated HC₆N₇(NH₂)₃ and non protonated C₆N₇(NH₂)₃ moieties in the coplanar layers as well as perchlorate ions between them, all of which being interconnected by hydrogen bonds. Vibrational spectroscopic investigations (FTIR and Raman) of the salt were conducted.