what is the most reactant chemical in the world?

Question: what is the most reactant chemical in the world?
- Keywords:
  chemistry,
  reactive,
  state
Asked by beth.nicholls to Angela, Claire, Ian, Robert, Sarah on 11 Nov 2014. This question was also asked by R Conachie, Thomas.Dingle.
- Ian Cade answered on 11 Nov 2014:
  
  Depends on the particular conditions, for example on Earth, with its oxygen rich atmosphere, strongly reducing materials like potassium are not stable.
  
  However, the one compound that comes to mind as being especially reactive is ClF3 which ignites such ‘inert materials’ as sand, concrete and asbestos!
  
  http://en.wikipedia.org/wiki/Chlorine_trifluoride
- Angela Stokes answered on 11 Nov 2014:
  
  I guess it also depends on what you want to make a reaction with?

Question: what is the most reactant chemical in the world?