The compound [C(NH 2) 3] 3FeF 6 is prepared in closed bombs by digestion of FeF 3 and C(NH 2) 3F in aqueous HF solutions. The material is cubic, space group Pa3, a = 14.130(5) Å, Z = 8. The crystal structure is determined from single-crystal diffraction intensity data refined to the conventional values of the indexes R = 0.0409 and Rw = 0.0409 for the model containing the nonhydrogen atoms. All the hydrogen atoms are located by the final difference-Fourier map and lie near N atoms at distances in the range 1.02 to 1.09 Å. The structure is characterized by two different sets of regular isolated (FeF 6) octahedra. Guanidinium cations are located on general 24-fold positions. The NH … F hydrogenbonding network is discussed. As expected, the compound is paramagnetic ( μexp = 6.01 μB, ϑp = -5.6 K) and characterized by Mössbauer spectroscopy.