Nitrogen trifluoride

Nitrogen trifluoride

Names
IUPAC name Nitrogen trifluoride
Other names Nitrogen fluoride Trifluoramine Trifluorammonia
Identifiers
CAS Number	7783-54-2 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:30231 Y
ChemSpider	22959 Y
ECHA InfoCard	100.029.097
EC Number	232-007-1
Gmelin Reference	1551
PubChem	24553
RTECS number	QX1925000
UN number	2451
InChI InChI=1S/F3N/c1-4(2)3 Y Key: GVGCUCJTUSOZKP-UHFFFAOYSA-N Y InChI=1/F3N/c1-4(2)3 Key: GVGCUCJTUSOZKP-UHFFFAOYAA
SMILES FN(F)F
Properties
Chemical formula	NF3
Molar mass	71.00 g/mol
Appearance	colorless gas
Odor	moldy
Density	3.003 kg/m3 (1 atm, 15 °C) 1.885 g/cm3 (liquid at b.p.)
Melting point	−207.15 °C (−340.87 °F; 66.00 K)
Boiling point	−129.06 °C (−200.31 °F; 144.09 K)
Solubility in water	0.021 g/100 mL
Vapor pressure	>1 atm (20°C)
Refractive index (nD)	1.0004
Structure
Molecular shape	trigonal pyramidal
Dipole moment	0.234 D
Thermochemistry
Specific heat capacity (C)	53.26 J/(mol·K)
Std molar entropy (So298)	260.3 J/(mol·K)
Std enthalpy of formation (ΔfHo298)	−31.4 kJ/mol −109 kJ/mol
Gibbs free energy (ΔfG˚)	−84.4 kJ/mol
Hazards
Safety data sheet	AirLiquide
NFPA 704	0 1 0 OX
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LC50 (median concentration)	2000 ppm (mouse, 4 hr) 9600 ppm (dog, 1 hr) 7500 ppm (monkey, 1 hr) 6700 ppm (rat, 1 hr) 7500 ppm (mouse, 1 hr)
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 10 ppm (29 mg/m3)
REL (Recommended)	TWA 10 ppm (29 mg/m3)
IDLH (Immediate danger)	1000 ppm
Related compounds
Other anions	nitrogen trichloride nitrogen tribromide nitrogen triiodide ammonia
Other cations	phosphorus trichloride arsenic trichloride antimony trichloride bismuth trichloride
Related binary fluoro-azanes	tetrafluorohydrazine
Related compounds	dinitrogen difluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Nitrogen trifluoride is the inorganic compound with the formula NF₃. This nitrogen-fluorine compound is a colorless, odorless, nonflammable gas. It finds increasing use as an etchant in microelectronics.

Nitrogen trifluoride is used in the plasma etching of silicon wafers. Today nitrogen trifluoride is predominantly employed in the cleaning of the PECVD chambers in the high-volume production of liquid-crystal displays and silicon-based thin-film solar cells. In these applications NF₃ is initially broken down in situ by a plasma. The resulting fluorine atoms are the active cleaning agents that attack the polysilicon, silicon nitride and silicon oxide. Nitrogen trifluoride can be used as well with tungsten silicide, and tungsten produced by CVD. NF₃ has been considered as an environmentally preferable substitute for sulfur hexafluoride or perfluorocarbons such as hexafluoroethane. The process utilization of the chemicals applied in plasma processes is typically below 20%. Therefore some of the PFCs and also some of the NF₃ always escape into the atmosphere. Modern gas abatement systems can decrease such emissions.

Elemental fluorine has been introduced as an environmentally friendly replacement for nitrogen trifluoride in the manufacture of flat-panel displays and thin-film solar cells.