Phase diagrams for binary salt solutions
Phase diagrams for several binary salt solutions are shown below. Click on the tabs to see solubility diagrams for:
- Sodium chloride – water
- Calcium chloride – water
- Magnesium nitrate – water
- Magnesium sulfate – water
- Tri-sodium phosphate – water
- Di-sodium phosphate – water
- Mono-sodium phosphate – water
The sodium chloride – water system
In the sodium chloride – water system, one eutectic point and one peritectic point is found. These points are shown in the phase diagram to the right.
The eutectic point is the cryohydratic point, where ice and NaCl·2H2O (hydrohalite) both are in equilibrium with the same saturated solution.
The peritectic point at 0.1 °C marks the transition between hydrohalite and anhydrous sodium chloride as the stable solid phase in equilibrium with a saturated sodium chloride solution. If heated, solid hydrohalite will at this temperature be transformed into anhydrous sodium chloride (NaCl) and a saturated solution of sodium chloride.
The eutectic point is at -21°C.
The peritectic point is at 0.1°C.