##  [Diffusivity](/index.php/diffusivity) 

  ##  [Diffusivity](https://engineering.quantumdictionary.io/diffusivity-0) 

  

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**Engineering & Applied Technologies Dictionary**

 







 

 

 

 



 

 

 

 

Definition

The proportionality coefficient D that relates species flux to concentration gradient in Fick's first law, J = −D ∇c, with SI units m2·s−1; it characterises molecular transport by random motion under conditions where continuum, dilute-solution and local equilibrium approximations hold, and depends on species, medium, temperature and pressure.