Crystal structure of the nonlinear optical compound L-arginine fluoride

L-arginine fluoride is a promising compound that exhibits nonlinear optical properties. It efficiently converts two single photons of the same polarization and frequency to one photon of frequency 2 (type I phase matching). C₆H₁₅N₄O₂⁺F^– is monoclinic, space group P2₁, a = 5.4475(4) Å, b = 8.5133(6) Å, c = 10.2195(7) Å, = 93.475(6)°. The cation has a zwitterionic form, protonated at both the guanidyl and amino groups. The arginine C atom is in a trans position to the carboxyl group. A complex three-dimensional hydrogen bond network links the anions and cations together.