Condensing to moderate pressures;
Evaporate at pressures above atmospheric;
Have small specific volume;
Have high latent heat of vaporization;
Be chemically stable (does not change despite repeated changes in the refrigeration circuit);
Don't be corrosive;
Not be flammable;
Don't be toxic;
It must allow easy location of leaks;
It must not attack the lubricating oil or have any undesirable effects on the other materials of the unit and
It should not attack or spoil food in the event of leaks.
It should not attack the ozone layer, in case of leaks.
