Some critics challenged its originality, claiming priority for other investigators, like van't Hoff, or Willard Gibbs. Others cited experiments whose outcomes do not appear to be in accord with it. One recent study, combining both approaches, argues that it is 'Neither Le Chatelier's nor a principle'. Today's students' texts generally mention Le Chatelier's principle, but tend to play down its significance. One book tries to make it more interesting to university students by applying it to the formation of carbon dioxide bubbles in a freshly opened bottle of beer.
Some elementary works do recognise that the principle is problematic.
14 Specialised works on physical chemistry are more explicit about the principle's limitations. One highlights the synthesis of ammonia from nitrogen and hydrogen - a reaction investigated in the laboratory by Le Chatelier himself, but developed industrially by Haber and Bosch. But the rate of reaction at low temperatures is so slow that it is more advantageous to work the process at higher temperatures - the yield is smaller, but it is delivered sooner. In fact, there have been many attempts to recast the principle in a more satisfactory form of words, or to replace it altogether with a thermodynamic equation. Some have produced interesting and useful results, but it seems that every gain in precision is accompanied by a loss of clarity, or of comprehensiveness.