The morphology of lepidocrocite crystals has been found to be significantly modified by the binding of certain hydroxybenzenes and aliphatic diols. The data have been combined in order to explore the geometric and stereochemical requirements of the binding process. Replacement of hydroxides by hydroxyl groups combined with appropriate iron-oxygen orbital overlap is found to be an essential requirement. Attempts to find molecules capable of binding to (010) were unsuccessful due either to the need for highly strained molecular conformations or due to the inherent passivity of the (010) surface.