= Solution
Using the <spin> values above and accounting for \b[two metal ions per formula unit],
$$
\boxed{g_{\rm Fe}=\sqrt{7.4/1.5}=2.22,\quad g_{\rm Co}=\sqrt{5.2/0.9375}=2.36,\quad g_{\rm Ni}=\sqrt{3.4/0.5}=2.61.}
$$
The deviations from 2 indicate <spin-orbit coupling> and incomplete quenching of <orbital angular momentum>. The partly filled $e''$ manifold in Fe and $e'$ manifold in Ni permit orbital degeneracy in the ideal geometry. Co's high-spin orbital occupation is more orbitally balanced, but mixing with excited ligand-field states still produces a substantial effective $g$ shift. These fitted scalar values summarize a thermally averaged response; they do not determine the individual components of an anisotropic <g tensor>.
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