It is an oxide of iron, the chemical formula is Fe3O4, and the relative molecular mass is 23 1.54. Ferroferric oxide is the only iron compound that can be magnetized in middle school. Fe3O4 contains Fe2+ and Fe3+. X-ray diffraction experiments show that Fe3O4 has an inverse spinel structure, and there is no ferrous ion FeO2 in the crystal. Ferroferric oxide is also called magnetic iron oxide, iron oxide black, magnet, magnet and magnet, and the natural mineral type is magnetite. There are two valence states of iron in ferroferric oxide, both of which are inverse spinel structures, namely Fe Ⅲ [Fe Ⅲ Fe Ⅱ] O4. In addition, ferroferric oxide is also a conductor, because Fe2+ and Fe3+ in ferroferric oxide are basically in octahedral disorder, and electrons can be rapidly transferred between the two oxidation states of iron, so ferroferric oxide solid has excellent conductivity.

silicon dioxide

Also known as silica. It is widely distributed in nature, such as timely and quartz sand. White or colorless, light yellow, with high iron content. The density is 2.2 ~ 2.66. Melting point 1670℃ (tridymite); 17 10℃ (in time). The boiling point is 2230℃ and the relative dielectric constant is 3.9. Insoluble in water, slightly soluble in acid, and can react with molten alkali when it is granular. Used for making glass, water glass, pottery, enamel, refractory, ferrosilicon, molding sand, elemental silicon, etc.