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For the complex ions [Ni(CN)4]²-, [MnBr4]²-, and [FeF6]⁴-, identify the correct combination of geometry, hybridization, and magnetic moment (in BM) in that order:

1. Tetrahedral, square planar, octahedral; sp3, dsp2, sp3d2; 5.9, 0, 4.9
2. Tetrahedral, square planar, octahedral; dsp2, sp3, sp3d2; 0, 5.9, 4.9
3. Square planar, tetrahedral, octahedral; dsp2, sp3, d2sp3; 5.9, 4.9, 0
4. Square planar, tetrahedral, octahedral; dsp2, sp3, sp3d2; 0, 5.9, 4.9

Correct answer: Square planar, tetrahedral, octahedral; dsp2, sp3, sp3d2; 0, 5.9, 4.9

Solution

[Ni(CN)4]²- has strong-field CN- forcing square planar dsp2 with all electrons paired (mu=0); [MnBr4]²- has weak-field Br- giving tetrahedral sp3 with 5 unpaired d electrons for Mn2+ (mu=5.92 BM); [FeF6]⁴- has weak-field F- giving octahedral sp3d2 with 4 unpaired d electrons for Fe2+ (mu=4.90 BM).

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