Diferro boride, Fe₂B

Iron sub-boride or diferro boride, Fe₂B, is obtained by heating reduced iron and boron in a porcelain tube in an atmosphere of hydrogen. It occurs as steel-grey prisms, of density 7.37 at 18° C., and is attacked by dry air at dull red heat only, whilst moist air readily attacks it at ordinary temperatures. It dissolves in hot aqueous solutions of the mineral acids.