Hydrogen fluoride

Metals, water or steam. [Note: Corrosive to metals. Will attack glass and concrete].

Interaction of the solid /bismuthic acid/ with 40% hydrofluoric acid is violent, ozonized oxygen being evolved.

Polymerization of cyanogen fluoride is rapid at ambient temp and explosive in presence of hydrogen fluoride.

A chemical polishing soln consisting of nitric acid and hydrofluoric acid (1 vol each) and glycerol (2 vols) generated enough pressure during storage for 4 hr to rupture the closed plastics container. This was caused by gas evolution from oxidation of glycerol by the strongly oxidizing mixture. A mixture of nitric acid (80 mL), hydrofluoric acid (80 mL) and glycerol (240 mL) was used immediately for etching metal, again the next day, and then stored in a stoppered flask. After some 2-3 days, the stopper was ejected and approx 300 mL was sprayed around the fume cupboard containing the flask. The metals dissolved during use further destabilize the mixture, which should not be stored under any circumstances.

During the fluorination of organic materials by passing hydrogen fluoride into a vigorously stirred suspension of the oxide (to form transiently mercury difluoride, a powerful fluorinator), it is essential to use adequate and effective cooling below 0 C to prevent loss of control of the reaction system.

Electrolysis of a mixture /of methanesulfonic acid and hydrogen fluoride/ produced oxygen difluoride which exploded.

Mixtures of the 3 acids /hydrofluoric acid, lactic acid, and nitric acid/, used as metal polishing solutions, are unstable and should not be stored. Lactic acid and nitric acid react autocatalytically after a quiescent period, attaining a temp of about 90 deg C with vigorous gas evolution after about 12 hr.

A chemical polishing mixture /of hydrofluoric acid, propylene glycol, silver nitrate, and nitric acid/ was put into a closed glass bottle which burst 30 min later, and formation of silver fulminate was suggested. However, in absence of the silver salt such mixtures evolve gas and should not be stored in any event, especially after use for metal polishing, when the dissolved metal(s) tend to further destabilize the mixture.

Arsenic trioxide and calcium oxide incandesce in contact with liquid hydrogen fluoride.

During preparation of potassium hexafluoromanganate(IV), addition of the solid oxidant /potassium permanganate/ to exceptionally concn hydrofluoric acid (60-90%, rather than 40% previously used) caused a violent exothem with light emission.

Contact /of potassium tetrafluorosilicate(2-)/ with liquid hydrogen fluoride causes violent evolution of silicon tetrafluoride.

Anhydrous hydrogen chloride, hydrogen fluoride or sulfuric acid react slowly with sodium, while the aqueous solutions react explosively.

A student was attempting to prepare anhydrous hydrogen fluoride by dehydrating aqueous 60% hydrogen fluoride solution with concn sulfuric acid. Addition of 200 mL of sulfuric acid to 500 mL of hydrofluoric acid in a 1 L copper flask led to a rumbling noise, then a fountain from the flask neck of hot mixed acids which severely corroded the window glass and the floor tiles.

Phosphorus pentoxide unites with hydrogen fluoride vigorously, even at 19.5 deg C.

If fluorine is passed into a 50% solution of hydrofluoric acid, there is an energetic reaction with the water and it is accompanied by flame. /Hydrofluoric acid, aqueous/

Incompatible materials: Metals, Alkali metals, Strong bases, glass