Chemistry 401

Intermediate Inorganic Chemistry

University of Rhode Island

Exam 3

December 6, 2013

1. For the following compounds or ions, give the systematic name, the point group, the crystal field stabilization energy (in units of Dq), the predicted spin-only magnetic moment (in units of Bohr-Magnetons), and determine the predcted distortion if the complex is Jahn-Teller active:

a. (Despite the drawing, the Fe-N-O and Fe-C-N bond angles are 180°.)

b.

c.

d.

Answer

2. For the following compounds or ions, give the systematic name, the point group,and predict if the complex will be stable:

a.

b.

c.

d.

Answer

3. For Co3+, the spin pairing energy is 21,000 cm–1 and Dq for NH3 (when bonded to Co3+) is 2,300 cm–1. Estimate the wavelength (in units of nm) for the lowest energy spin-allowed d-d transition in [Co(NH3)6]3+. Useful information: nm = 107/cm–1; ν = 10Dq for d6 high spin; and ν ~ 9Dq for d6 low spin.

Answer

Spectrochemical series: I < Br < S2– < SCN < Cl < NO3 < F < ox2– < H2O < SCN < CH3CN < NH3 < en < bipy < phen < NO2 < PPh3 < CN < CO (the underlined atom is the one attached to the metal). ox = oxalate; en = ethylenediamine; bipy = 2,2'-bipyridine; phen = phenanthroline; Ph = phenyl.