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.

 

[CandyBarff]

Millimolar (mM) is a unit of concentration used in chemistry. It means one-thousandth of a molar (M) solution.

• 1 molar (1 M) = 1 mole of solute per liter of solution
• 1 millimolar (1 mM) = 0.001 moles per liter = 10⁻³ M

For example, a 5 mM NaCl solution contains 0.005 moles of sodium chloride per liter of solution.