Iron(II-III) hydroxysulphate precipitates were prepared in absence of other compounds by coprecipitation that consists of mixing solutions of iron(II) and iron(III) salts with NaOH solution in adequate proportions. Precipitates were characterised by transmission Mössbauer spectroscopy (TMS), XRD, TEM and AFM. Mössbauer spectrum measured at 15 K was composed of Fe(II) and Fe(III) doublets with δ=1.33 and 0.51 mm s -1, and Δ=2.88 and 0.43 mm s -1, respectively. The Fe(II)/Fe(III) ratio of 2 is independent of the solution ratio set at 3 that confirms the composition, [Fe II4Fe III2(OH) 12] 2+·[SO 2-4 · m H 2O] 2-. XRD analysis led to hexagonal unit cell parameters of aH= bH=0.318±0.004 nm and cH=1.090±0.004 nm. The value aH=0.314±0.002 nm was obtained by TEM diffraction pattern corresponding to ( h k 0 ) planes and displayed a distribution of hexagonal plates (10