What is millimolar?

[Deepak]

I keep seeing the term "millimolar" in chemistry topics. What does it mean, and how is it different from molar concentration?

 

[Salvatore_Damon]

Millimolar (mM) is just a way to express concentration. It means one-thousandth of a molar (M), so 1 mM = 0.001 M. I use it a lot in lab work when I need very dilute solutions.