THE MAGNETIC-STRUCTURE OF BERNALITE, FE(OH)(3)

Mossbauer spectra of bernalite, a recently described mineral with a di storted perovskite-type structure and chemical formula Fe(OH)(3), were recorded at 4 K in external magnetic fields up to 6 T to obtain infor mation about the magnetic structure. Spectra show a single hyperfine m agnetic component, where the angle between the net magnetic moment and the direction of the external field is close to 90 degrees. The most likely spin arrangement is a slight deviation from a collinear antifer romagnet, resulting in a weak ferromagnetic moment.