Mössbauer Study of β‐ and δ‐FeOOH and their Disintegration Products

Abstract β‐FeOOH and δ‐FeOOH are studied by Mössbauer effect measurements. The Néel point of β‐FeOOH is T N = (295 ± 4) °K. Above this temperature the material is paramagnetic with quadrupole splitting and it decomposes to α‐Fe 2 O 3 at 670 °K. The transition at this temperature takes 12 hours. The two internal magnetic fields observed in δ‐FeOOH are found to correspond to Fe 3+ ions in octahedral and tetrahedral positions. δ‐FeOOH decomposes to intermediate products at 370 °K below its Curie Temperature and it disintegrates to α‐Fe 2 O 3 at approximately 510 °K.

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