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CAIE A-Level Chemistry 28.4.2 Overall Polarity of Complexes

Practise deducing whether complex stereoisomers are polar by testing the cancellation of bond dipoles in 3D.

Syllabus
2028–2030
Course
Chemistry 9701
Level
A2

Exam points

  • use the complete three-dimensional structure rather than the complex charge alone to assess polarity
  • identify a symmetric trans arrangement as non-polar when equal opposing bond dipoles cancel
  • identify a cis arrangement as polar when its polar bonds are arranged so their dipoles do not cancel

28.4.2—The overall polarity of complexes such question 1

[Maximum number: 2]

Titanium is a transition element in Period 4. It is commonly found as TiO2\mathrm{TiO}_{2} in minerals.

Some reactions of TiO2\mathrm{TiO}_{2} are shown in Fig. 3.1.

The anion, acac −^{-}, is a bidentate ligand.

Fig. 3.1

Fig. 3.1

The acac- anion is symmetrical.

Deduce which, if any, of stereoisomers 1, 2 and 3 in (d)(iv) are polar. Explain your answer.

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