In the nitrate ring test, the brown species [Fe(H2O)5NO]^2+ is best described by treating NO as the nitrosonium ligand NO+. Assuming the complex is high spin, the oxidation state of iron and the spin-only magnetic moment (BM) are respectively

JEE Advanced levelSingle correct optionDifficulty 3 of 3qa088

In the nitrate ring test, the brown species $[Fe (H X_{2} O) X_{5} NO] X^{2 +}$ is best described by treating NO as the nitrosonium ligand $NO X^{+}$ . Assuming the complex is high spin, the oxidation state of iron and the spin-only magnetic moment (BM) are respectively

Charge balance:

x + 0 + 1 = + 2

gives

x = + 1

. Fe(I) is

d^{7}

; in the high-spin arrangement there are three unpaired electrons, so

μ = 3 \times 5 = 15 = 3.87

BM. This is consistent with the observed paramagnetism of the brown ring complex.