Solubility: soluble in water, slightly soluble in alcohol, insoluble in Aether and most organic solvents.
Acid: a weak acid.
Appearance: crystalline compounds, aqueous acid.
Ionization constants: Ka==2.5x10 ˉt acid 4 acid is usually a five Yuan,H5G said. With Fe complex structure formed, with the change in solution pH increased gradually, and finally forms mixed complexes of hydroxy.