553.    CHEVALIER, R., MATHIEU, S., AND GIRARD, J.  [Monograph of Ferrous Boroferrite.]  Bull. Soc. Chim., vol. 15, 1948, pp. 611-615; Chem. Abs., vol. 42, 1948, p. 7649.

                 Mixture of 2 gm. Fe₂O₃ and 3 gm. Na₂B₄O₇, heated in a Pt boat at 1,000°, is reduced with either H₂ or CO; the cooled mass is treated with 3 N HNO₃, and the residue is dried after being washed with hot H₂O.  Likewise the oxidation of a mixture of 2 gm. fine Fe and 4 gm. Na₂B₄O₇, heated in N₂ at 1,000° and oxidized with air, yields crystals of the boroferrite B₂O₃.Fe₂O₃.4 FeO.  the product appears as fine black, opaque, orthorhombic crystalline needles.  The boroferrite is readily attacked by dilute HCl, but less readily by H₂SO₄ and HNO₂; the resulting solution shows properties of B₂O₃.Fe²⁴ and Fe³⁴.  The constitution is believed to be

                                                O                        O

                                                          /     \                  /     \

                                                       Fe      B  –  O  –  Fe     Fe

                                                          \     /                    \     /

                                                            O                        O