Shapes of complex ions

• 4 shapes of complex ions :

  • Linear
  • Square planar
  • Tetrahedral
  • Octahedral
• Complexes have different shapes due to the coordination number and size of ligands
• Square planar e.g. is nickel ( || ) tetracyano ion

  • Has a charge of 2-
  • Has a coordination number of 4.
• Tetrahedral e.g. is cobalt (||) chloride ion

  • Has a 2- charge
  • Has a coordination number of 4

  
• Cis-trans isomerism occurs because ligands cannot rotate around the central metal ion. Formed by complexes with monodentate ligands.
• Platin can either be cisplatin or transplatin with cisplatin having the same formula group 90 ° from each other while transplatin has them 180 ° from each other
• Which platin is the diagram?

  Cisplatin

  
• Which platin is in the diagram?

  Transplatin

  
• Different steriosomers can have different chemical properties e.g. Cisplatin is an isomer which is an anti cancer drug but transplatin has no medical uses
• Cis-trans in octerhedral complex ion can happen if they have 4 ligands of one type and 2 of another

  • If the 2 odd ligands are opposite each other (180 °) they are trans
  • If the 2 odd ligands are next to each other (at least 90 ° ) they are cis
• Cisplatin is injected into cancer patients as they are useful in treating solid tumours as it prevent DNA from unwinding by forming coordinate bonds with DNA bases so DNA can't replicate
• Disadvantage of cisplatin:

  • It also affects healthy cells
  • Loads of side effects
  • If patient has too much of it they could be come resistant to it
• Optical isomerism is where a molecule can exist as two forms that are non superimposable mirror images of each other (left and right hand).

  • Formed by octahedral complexes with bidentate ligands