Barium ferrite 2996474 215455553 2008-05-28T08:03:21Z DOI bot 6652755 Citation maintenance. You can [[WP:DOI|use this bot]] yourself! Please [[User:DOI_bot/bugs|report any bugs]]. '''Barium ferrite''', abbreviated BaFe, is the [[chemical compound]] with the [[chemical formula|formula]] BaFe<sub>2</sub>O<sub>4</sub>. This and related [[Ferrite (iron)|ferrite]] materials are components in [[magnetic stripe card]]s. BaFe is described as Ba<sup>2+</sup>(Fe<sup>3+</sup>)<sub>2</sub>(O<sup>2-</sup>)<sub>4</sub>. The Fe<sup>3+</sup> centers, with a [[Crystal field theory|high-spin]] d<sup>5</sup> configuration, are [[ferromagnetism|ferromagnetic]]ally coupled.<ref>{{cite book | author = Shriver, D. F.; Atkins, P. W.; Overton, T. L.; Rourke, J. P.; Weller, M. T.; Armstrong, F. A. | title = Inorganic Chemistry | publisher = [[W. H. Freeman]] | location = New York | year = 2006 | isbn = 0-7167-4878-9}}</ref> This area of technology is usually considered to be an application of the related fields of [[materials science]] and [[solid state chemistry]]. It is also used in [[subwoofer]] magnets to provide power. A related family of industrially useful "hexagonal ferrites" are known, also containing barium. In contrast to the usual spinel structure, these materials feature hexagonally close-packed framework of oxides. Furthermore some the oxygen centers are replaced by Ba<sup>2+</sup> ions. Formulas for these species include BaFe<sub>12</sub>O<sub>19</sub>, BaFe<sub>15</sub>O<sub>23</sub>, and BaFe<sub>18</sub>O<sub>27</sub>.<ref>{{cite journal | author = Y. Goto, T. Takada | title = Phase Diagram of the System BaO-Fe<sub>2</sub>O<sub>3</sub> | journal = Journal of the American Ceramic Society | year = 1960 | volume = 43 | issue = 3 | pages = 150–153 | doi = 10.1111/j.1151-2916.1960.tb14330.x }} </ref> Thus, BaFe<sub>12</sub>O<sub>19</sub> is related to Fe<sub>12</sub>O<sub>20</sub>, with the empirical formula Fe<sub>3</sub>O<sub>4</sub>, i.e. [[magnetite]].<ref>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.</ref> Barium ferrites are robust [[ceramic]]s that are generally stable to moisture and corrosion-resistant.<ref>{{cite journal | author = C. Okazaki, S. Mori, F. Kanamaru | title = Magnetic and Crystallographical Properties of Hexagonal Barium Mono-Ferrite, BaO·Fe<sub>2</sub>O<sub>3</sub> | journal = Journal of the Physical Society of Japan | year = 1961 | volume = 16 | issue = 3 | pages = 119–119 | doi = 10.1143/JPSJ.16.119 | url = http://jpsj.ipap.jp/link?JPSJ/16/119/ }} </ref> ==References== <references/> [[Category:Barium compounds]] [[Category:Iron compounds]] [[Category:oxides]] {{material-stub}} [[ar:فيريت باريوم]]