Neutron Diffraction Studies of α‐FeOOH

Abstract Neutron spectrometric investigations are made of goethite (α‐FeOOH) of mineralogical and synthetic origin (α‐FeOOH of natural isotopic composition) and also of α‐FeOOD using a monochromatic neutron beam of λ = 1.12 Å. Some powder diffraction patterns in the temperature range from −190 to +120°C are measured. The obtained coordinates for all atoms (including those for hydrogen) in the unit cell are given. The existence of antiferromagnetic spin ordering at temperatures below +80°C is observed. A model is proposed in which the spins are aligned parallel to the b ‐axis.