From: Poutnik4NNTP@gmail.com   
      
   On 12/03/2015 11:27 AM, Martin Brown wrote:   
   >   
   > How sensitive to choice of reagents is the BZ reaction in practice?   
   >   
   > I have always previously demo'd it in 1M sulphuric acid with the classic   
   > ceric suphate, potassium bromate & malonic acid in the yellow to clear   
   > form with or without ferroin to get a higher contrast.   
   >   
   > It works easily over a wide range of composition and temperatures with   
   > these reagents and I have never had it fail to oscillate.   
   >   
   > But will it also run with other adjacent f group elements like say   
   > neodymium to get a pink to clear solution?   
      
   >   
   > If not what is so special about cerium in this reaction?   
   >   
   > Failing that how about thorium and uranium sat in the corresponding   
   > positions in the next row down?   
   >   
      
   There is important to have a kation redox system,   
   like Ce(III) <> Ce(IV) with suitable standard redox potential.   
   I have seen also a link of usage MnSO4,   
   as Mn(II)<>Mn(III) creates similar system.   
      
   Some redox reactions have both reactants of the same charge,   
   or related nucleofilic/electrofilic afinity.   
   In such case they are often catalyzed by redox system of the opposite   
   charge, frequently with usage of transient metals like Mn, Fe, Cu.   
      
   There is different relation of d and f orbital energies for lanthanoids   
   and actinoids, therefore chemical properties of respective element do   
   not match well. E.g. Neodymium as a counterpart of Uranium does not have   
   oxidation number VI.   
      
      
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