Problem 1
Comment on (a) the observation of variable oxidation states among elements of the \(s\) - and \(p\) -blocks, and (b) the statement that "variable oxidation states are a characteristic feature of any \(d\) -block metal'.
Problem 2
(a) Write down, in order, the metals that make up the first row of the \(d\) -block and give the ground state valence electronic configuration of each element. (b) Which triads of metals make up groups 4,8 and \(11 ?\) (c) Which metals are collectively known as the platinum-group metals?
Problem 5
Give a brief overview of properties that characterize a \(d\) -block metal.
Problem 6
Suggest why (a) high coordination numbers are not usual for first row \(d\) -block metals, (b) in early \(d\) -block metal complexes the combination of a high oxidation state and high coordination number is common, and (c) in first row \(d\) -block metal complexes, high oxidation states are stabilized by fluoro or oxo ligands.
Problem 7
For cach of the following complexes, give the oxidation state of the metal and its \(d^{n}\) configuration: (a) \(\left[\mathrm{Mn}(\mathrm{CN})_{6}\right]^{4-} ;(\mathrm{b})\left[\mathrm{FeCl}_{4}\right]^{2-} ;(\mathrm{c})\left[\mathrm{CoCl}_{3}(\mathrm{py})_{3}\right]\) (d) \(\left[\mathrm{ReO}_{4}\right]^{-} ;\) (e) \(\left[\mathrm{Ni}(\mathrm{en})_{3}\right]^{2+}\) \((\mathrm{f})\left[\mathrm{Ti}\left(\mathrm{OH}_{2}\right)_{6}\right]^{3+}\) \((\mathrm{g})\left[\mathrm{VCl}_{6}\right]^{3-} ;(\mathrm{h})\left[\mathrm{Cr}(\mathrm{acac})_{3}\right]\)
Problem 8
Within the Kepert model, what geometries do you associate with the following coordination numbers: (a) \(2 ;(b) 3 ;(c) 4 ;(d) 5 ;(c) 6 ?\)
Problem 10
(a) In the solid state, \(\mathrm{Fe}(\mathrm{CO})_{5}\) possesses a trigonal bipyramidal structure. How many carbon environments are there? (b) Explain why only one signal is observed in the \(^{13} \mathrm{C} \mathrm{NMR}\) spectrum of solutions of \(\mathrm{Fe}(\mathrm{CO})_{5},\) even at low temperature.
Problem 13
What chemical tests would you use to distinguish between (a) \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Br}\right]\left[\mathrm{SO}_{4}\right]\) and \(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5}\left(\mathrm{SO}_{4}\right)\right] \mathrm{Br},\) and (b) \(\left[\mathrm{CrCl}_{2}\left(\mathrm{OH}_{2}\right)_{4}\right] \mathrm{Cl} \cdot 2 \mathrm{H}_{2} \mathrm{O}\) and \(\left[\mathrm{CrCl}\left(\mathrm{OH}_{2}\right)_{5}\right] \mathrm{Cl}_{2} \cdot \mathrm{H}_{2} \mathrm{O} ?\) (c) What is the relationship between these pairs of compounds? (d) What isomers are possible for \(\left[\mathrm{CrCl}_{2}\left(\mathrm{OH}_{2}\right)_{4}\right]^{+}\)
Problem 15
What isomers would you expect to exist for the platinum(II) compounds: (a) \(\left[\mathrm{Pt}\left(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CHMeNH}_{2}\right)_{2}\right] \mathrm{Cl}_{2},\) and (b) \(\left[\mathrm{Pt}\left(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CMe}_{2} \mathrm{NH}_{2}\right)\left(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CPh}_{2} \mathrm{NH}_{2}\right)\right] \mathrm{Cl}_{2} ?\)
Problem 16
How many different forms of \(\left[\mathrm{Co}(\mathrm{en})_{3}\right]^{3+}\) are possible in principle? Indicate how they are related as enantiomers or diastereomers.
