Customizable Sodium Aluminum Fluoride Cryolite Used As Fluxes For Welding Wires Physical properties: colorless triclinic crystals. White powder or orthorhombic great six-sided crystals. Density 3.00g / cm3. Melting point 1040 ℃. Boiling Point (sublimation) 1272 ℃. There are several hydrates exist; slightly soluble in water, soluble in hot water. Difficult to dissolve in acid and alkali solution, insoluble in most organic solvents. It can be heated to 300-400 ℃ steam partial