# Negative reaction orders

by MathewsMD
Tags: negative, orders, reaction
 P: 384 Negative reaction orders I certainly don't know every single possibility that can occur in kinetics but my gut tells me that for an elementary step you shouldn't have negative reaction orders since the coefficients are the exponents. Maybe someone with more knowledge can help for the elementary step case. For an overall rate law I can see non integer as well as negative orders being possible because overall rate laws, as I mentioned, can be freaky looking. Think about what $\frac{dy}{dt}=k x^{-1}$ means. It doesn't mean that anything necessarily goes backwards, just that the instantaneous change of y as a function of time gets smaller as x gets larger.