Sample of magnetite, naturally occurring<unk> 3O4.<unk> 3O4 is<unk> rrimagnetic with a Curie temperature of 858 K. There is a phase transition at 120K, called Verwey transition where there is a discontinuity in the structure, conductivity and magnetic properties. This effect has been extensively investigated and whilst various explanations have been proposed, it does not appear to be fully understood. While it has much higher electrical resistivity than<unk>  metal (96.1 nΩ m),<unk> 3O4's electrical resistivity (0.3 mΩ m ) is significantly lower than that of<unk> 2O3 (approx kΩ m). This is ascribed to electron exchange between the<unk> II and<unk> III centres in<unk> 3O4.
Iron
Zinc
Copper 
Biotin
Folate
Selenous acid
Calamine
Sybil 