(Di­methyl­phosphor­yl)methanaminium iodide–(di­methyl­phosphor­yl)methan­amine (1/1)

The asymmetric unit of the title structure, C₃H₁₁NOP⁺·I⁻·C₃H₁₀NOP, consists of one (di­methyl­phosphor­yl)methanamine (dpma) mol­ecule, one (di­methyl­phosphor­yl)methanaminium (dpmaH) ion and one iodide counter-anion. In the crystal, medium–strong to weak N—H...O and N—H...N hydrogen bonds connect dpmaH cations and dpma mol­ecules into strands along [001]. The iodide counter-anions form only very weak hydrogen bonds. The crystal used for the diffraction study was found to be an inversion twin with a ratio of 0.83 (2):0.17 (2). The title structure is isotypic to that of dpmaH[ClO₄]·dpma [Buhl et al. (2013). Crystals 3, 350–362].