Fine acicular alpha-ferric oxide and production thereof.

摘要

Disclosed herein is fine acicular alpha -ferric oxide which has the crystallite diameter (D1014) in the direction perpendicular to the (1014) plane and the crystallite diameter (D1120) in the direction perpendicular to the (1120) plane such that their ratio D1014/D1120 is in the range of 1-2, and also has a specific surface area of 40-50 m<2>/g. Disclosed also herein is fine acicular alpha -ferric oxide which has the crystallite diameter (D1014) in the direction perpendicular to the (1014) plane and the crystallite diameter (D1120) in the direction perpendicular to the (1120) plane such that their ratio D1014/D1120 is in the range of 1-2, andalso has an average aspect ratio of 10-15 and a specific surface area of 20-40 m<2>/g. They are produced by wet process including the step of hydrothermal reaction.