The most important oxides of iron are magnetite, $\mathrm{Fe}_{3} \mathrm{O}_{4}\(, and hematite, \)\mathrm{Fe}_{2} \mathrm{O}_{3} .$ (a) What are the oxidation states of iron in these compounds? (b) One of these iron oxides is ferrimagnetic, and the other is antiferromagnetic. Which iron oxide is more likely to be ferrimagnetic? Explain.

The oxidation state of an element in a compound refers to the hypothetical charge that the atom would have if all its bonds were broken, with the bonded electron pairs distributed according to certain rules. In this case, we are looking to determine the oxidation state for iron in both magnetite (Fe3O4) and hematite (Fe2O3). To find the oxidation states of iron in both compounds, we can set up an equation where the total charges of iron atoms in each compound equals the total negative charges of the oxygen atoms. Since the charge on an oxygen atom is -2, the total negative charge for the oxygen atoms in magnetite will be 4*(-2)=-8, and for hematite, it will be 3*(-2)=-6. For example: In magnetite, x*Fe3 = -8 In hematite, y*Fe2 = -6 We need to solve for x and y to find the oxidation states of iron in these compounds.

In magnetite: Let's assume the oxidation state of iron as x. 3x = -8 x = -8/3 Since iron can't have a fractional oxidation state, this implies that there are two different oxidation states for iron in magnetite. We can rewrite the equation as: 2(Fe(II)) + Fe(III) = -8 Fe(II) represents iron with an oxidation state of +2, and Fe(III) represents iron with an oxidation state of +3. 3(+2) + (+3) = -8 6 + 3 = 9 In hematite: Let's assume the oxidation state of iron as y. 2y = -6 y = -6/2 y = +3 So, the oxidation state of iron in hematite is +3.

Ferrimagnetic substances are materials that display magnetic properties based on the different orientations and magnitudes of the atomic magnetic moments within the material. These substances have their unpaired electron spins aligned in opposite directions on different sublattices, resulting in a net spontaneous magnetization. Antiferromagnetic substances are materials in which the magnetic moments of adjacent atoms or ions cancel each other out, resulting in a net magnetic moment of zero. In antiferromagnetic substances, the unpaired electron spins on neighboring atoms align in opposite directions.

We know that magnetite (Fe3O4) has iron with two different oxidation states, Fe(II) and Fe(III). This difference in oxidation states leads to different magnitudes of magnetic moments within the material. Since ferrimagnetic substances are characterized by a difference in the orientation and magnitude of magnetic moments, it is reasonable to conclude that the iron oxide with different oxidation states, magnetite, is more likely to be ferrimagnetic. On the other hand, hematite (Fe2O3) has iron with only one oxidation state, Fe(III). The equal magnitudes of magnetic moments in hematite make it more likely to be antiferromagnetic, as the moments can cancel each other out and result in a net magnetization of zero. In conclusion, magnetite (Fe3O4) is more likely to be ferrimagnetic, while hematite (Fe2O3) is more likely to be antiferromagnetic.