Multi-domainic goethite

Conditions which promote multi-domainic goethites are high ionic strength (either [KOH] or salt) and also low synthesis temperature (<40°C). In alkaline solutions, multi-domainic character decreases and domain width increases as Al substitution increases to Al/(Fe-i-Al) of 0.15, whereas at Al/( Al-nFe) >0.15 single domain crystals result (Schulze Schwertmaim, 1984 Mann et al., 1985). Multidomainic goethites can recrystallize to single domain crystals as a result of hydrothermal treatment at 125-180 °C (Fig. 4.9) (Schwertmann et al., 1985). 

Cornell, R. M. and Giovanoli, R. (1986) Factors that govern the formation of multi-domainic goethites. Clays Clay Min. 34 557-564. 

Most of the published studies on the reaction of ions with iron oxides have used samples of oxides which have been exposed to various extents to carbon dioxide. Models fitted to data from such studies do not reflect fundamental characteristics of the surface but are affected by the degree of exposure to carbon dioxide. In the case of goethite, most of the samples have consisted of multi-domainal crystals. It is only when such crystals have been healed by hydrothermal treatment that the true adsorption reactions of the surface can... 

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