7783-54-2

A colorless gas with a moldy odor. Very toxic by inhalation. Slightly soluble in water. Corrosive to tissue. Under prolonged exposure to fire or heat the containers may rupture violently and rocket. Used to make other chemicals and as a component of rocket fuels.

NITROGEN TRIFLUORIDE(7783-54-2) is a very powerful oxidizing agent. Presents dangerous fire hazard in the presence of reducing agents. Etches glass in the presence of moisture. Emits toxic and corrosive fumes of fluoride when heated to decomposition [Lewis, 3rd ed., 1993, p. 937]. Can react violently with hydrogen, ammonia, carbon monoxide, diborane, hydrogen sulfide, methane, tetrafluorohydrazine, charcoal. Explosive reaction with chlorine dioxide. A severe explosion may occur when exposed to reducing agents under pressure [Bretherick, 5th ed., 1995, p. 1427].

Slightly soluble in water.

Severe explosion hazard. Corrosive to tissue. Methemoglobinemia, liver and kidney damage.

Vapors may cause dizziness or asphyxiation without warning. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire may produce irritating and/or toxic gases.

This material has been used in chemical synthesis and as an oxidizer for high-energy fuels (as an oxidizer in rocket propellant combinations).

Substance does not burn but will support combustion. Some may react explosively with fuels. May ignite combustibles (wood, paper, oil, clothing, etc.). Vapors from liquefied gas are initially heavier than air and spread along ground. Runoff may create fire or explosion hazard. Containers may explode when heated. Ruptured cylinders may rocket.

If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit. If frostbite has occurred, seek medical attention immediately; do NOT rub the affected areas or flush them with water. In order to prevent further tissue damage, do NOT attempt to remove frozen clothing from frostbitten areas. If frostbite has NOT occurred, immediately and thoroughly wash contaminated skin with soap and water.

UN2451 Nitrogen trifluoride, Hazard Class: 2.2; Labels: 2.2-Nonflammable compressed gas; 5.1-Oxidizer. Cylinders must be transported in a secure upright position, in a well-ventilated truck. Protect cylinder and labels from physical damage. The owner of the compressed gas cylinder is the only entity allowed by federal law (49CFR) to transport and refill them. It is a violation of transportation regulations to refill compressed gas cylinders without the express written permission of the owner.

The gas is a powerful oxidizer. Presents dangerous fire hazard in the presence of reducing agents. Etches glass in the presence of moisture. Reacts with oil, grease, reducing agents and other oxidizable materials; combustibles, organics, ammonia, carbon monoxide; methane, hydrogen, hydrogen sulfide; activated charcoal; diborane, water. Can react violently with hydrogen, ammonia, carbon monoxide, diborane, hydrogen sulfide, methane, tetrafluorohydrazine, charcoal. Nitrogen trifluoride will increase intensity of an existing fire.

Nitrogen trifluoride is a colorless gas. Moldy odor. Shipped as a nonliquefied compressed gas.

Return refillable compressed gas cylinders to supplier. Vent into large volume of concentrated reducing agent (bisulfites, ferrous salts or hypo) solution, then neutralize and flush to sewer with large volumes of water.

Colorless gas; moldy odor; liquefies at -128.75°C; density of liquid 3.116 g/mL; vapor pressure at -158°C 96 torr; solidifies at -206.8°C; critical temperature -39.15°C; critical pressure 44.02 atm; critical volume 126 cm³/mol; very slightly soluble in water.

ChEBI: Nitrogen trifluoride is a nitrogen halide.

Nitrogen trifluoride is prepared by electrolysis of either molten ammonium fluoride, NH₄F, or melted ammonium acid fluoride, NH₄HF₂ (or ammonium fluoride in anhydrous HF). While the NH₄F method is preferred because it forms nitrogen trifluoride as the only product, electrolysis of ammonium acid fluoride yields a small amount of dinitrogen difluoride, N₂F₂,and NF₃.
Also, nitrogen trifluoride can be prepared by reaction of ammonia with fluorine diluted with nitrogen in a reactor packed with copper. Other nitrogen fluorides, such as N₂F₂, N₂F₄, and NHF₂ also are produced. The yield of major product depends on fluorine/ammonia ratio and other conditions.

Nitrogen trifluoride can be formed from a wide variety of chemical reactions. The commercial process for production involves direct fluorination of ammonia with fluorine gas in the presence ofammonium fluoride.

Hydrogen reacts with nitrogen trifluoride with the rapid liberation of large amounts of heat and is the basis for the use of nitrogen trifluoride in high-energy chemical lasers. The flammability range for nitrogen trifluoride-hydrogen mixtures is 9.4 mole percent to 95 mole percent nitrogen trifluoride. Nitrogen trifluoride reacts with organic compounds, but generally an elevated temperature is required to initiate the reaction. Under these conditions, the reaction will often proceed explosively, and great care must be exercised when exposing nitrogen trifluoride to organic compounds. Therefore, nitrogen trifluoride has found little use as a fluorinating agent for organic compounds.

Nitrogen trifluoride has been used successfully in large quantities as a fluorine source for high-energy chemical lasers. It is preferred over fluorine because of its comparative ease of handling at ambient conditions.
Recently, an increasing amount of nitrogen trifluoride is being used in the semiconductor industry as a dry etchant, showing significantly higher etch rates and selectivities when compared to carbon tetrafluoride and mixtures of carbon tetrafluoride and oxygen.
Nitrogen trifluoride was also used as an oxidizer in rocketry in the early 1960s, but this application was not commercialized.

At temperatures less than 482°F (250°C), nitrogen trifluoride has a reactivity similar to that of oxygen and is relatively inert to most materials of construction. At ambient temperatures, brass, aluminum, copper, steel, and stainless steels can be used because corrosion rates of less than 0.1 mil/yr. at 160°F (71.1°C) have been determined for these materials. Nitrogen trifluoride is also compatible with fluorinated materials such as Teflon at ambient temperatures. At increased temperatures and pressures, nitrogen trifluoride's reactivity increases becoming more like that of fluorine, with nickel and Monel being the preferred materials of construction.

ACGIH recommends a Threshold Limit ValueTime-Weighted Average (TLV-TWA) of 10 ppm (29 mgim3) for nitrogen trifluoride. The TLV- TWA is the time-weighted average concentration for a nonnal 8-hour workday and a 40-hour workweek, to which nearly all workers may be repeatedly exposed, day after day, without adverse effect.
OSHA lists an 8-hour Time-Weighted Average-Pennissible Exposure Limit (TWA-PEL) of 10 ppm (29 mg/m3) for nitrogen trifluoride. TWA-PEL is the exposure limit that shall not be exceeded by the 8-hour TWAin any 8-hour work shift of a 40-hour workweek.
The toxicity of nitrogen trifluoride is related to its capacity to fonn methemoglobin, a modified fonn of hemoglobin incapable of oxygen transport, and to destroy red blood cells (hemolysis). Upon cessation of exposure, methemoglobin spontaneously reverts to hemoglobin. However, at high levels of exposure, therapeutic intervention may be necessary (oxygen, methylene blue, exchange transfusion). The occurrence of hemolysis requires careful monitoring for degree of anemia and the potential for impaired kidney function.
Nitrogen trifluoride's TLV-TWA value of 10 ppm resulted from a study that exposed rats to 100 ppm for 7 hours per day, 5 days per week for 18 months. No changes were detected in the animals' behaviors, heart or lung rates, blood levels, or appearance of fluorosis. ACGIH set the TLV-TWA at III 0 ofthe test level.
Gaseous nitrogen trifluoride is considered innocuous to the skin and a minor irritant to the eyes and mucous membranes.

Nitrogen trifluoride cylinders must be securely supported while in use to prevent movement and straining of connections. Full cylinders must be stored in a well-ventilated area, protected from excessive heat (125°F or 51.7°C), located away from organic or flammable materials, and secured. Valve protection caps and valve outlet caps must be securely in place at all times when the cylinder is not in use.

The toxicity of nitrogen trifluoride is related to its capacity to fonn methemoglobin, a modified fonn of hemoglobin incapable of oxygen transport, and to destroy red blood cells (hemolysis). Upon cessation of exposure, methemoglobin spontaneously reverts to hemoglobin. However, at high levels of exposure, therapeutic intervention may be necessary (oxygen, methylene blue, exchange transfusion). The occurrence of hemolysis requires careful monitoring for degree of anemia and the potential for impaired kidney function.

The initial threshold screening level (ITSL) for nitrogen trifluoride is 290 μg/m3 based on an 8 hr. averaging time.

Nitrogen trifluoride is available in grades ranging from 98 percent to 99.995 percent v/v minimum purity.