The Collaborative International Dictionary of English v.0.48:

Stoichiometric \Stoi`chi*o*met"ric\, Stoichiometrical
\Stoi`chi*o*met"ric*al\, a.
   Of or pertaining to stoichiometry; employed in, or obtained
   by, stoichiometry.
   [1913 Webster]

   2. (Chem.) of, pertaining to, using, or consuming, reagents
      in the exact proportions required for a given reaction;
      as, a stoichiometric reaction, i. e., a reaction which
      goes to completion, rather than stopping partway at an
      equilibrium point.
      [PJC]

WordNet (r) 3.0 (2006):

stoichiometric
    adj 1: of or relating to stoichiometry