This page provides supplementary chemical data on ammonia.
Molecular structure | |
---|---|
Point group | C3v |
Bond length | 101.2 pm (N–H)[1] |
Bond angle | 106.7° (H–N–H)[1] |
Bond strength | 435 kJ/mol (H–NH2) |
Crystal data | |
Crystal structure | ? |
Properties | |
Dipole moment | 1.46 D |
Dielectric constant | 22 ε0 at 239 K |
Magnetic susceptibility | diamagnetic |
Acidity of NH4+ (pKa) | 9.25 |
Phase behavior | |
---|---|
Triple point | 195.4 K (−77.75 °C), 6.060 kPa |
Critical point | 405.5 K (132.3 °C), 11.300 MPa |
Std enthalpy change of fusion, ΔfusH |
+5.653 kJ/mol |
Std entropy change of fusion, ΔfusS |
+28.93 J/(mol·K) |
Std enthalpy change of vaporization, ΔvapH |
+23.35 kJ/mol at BP of −33.4 °C |
Std entropy change of vaporization, ΔvapS |
+97.41 J/(mol·K) at BP of −33.4 °C |
Solid properties | |
Std enthalpy change of formation, ΔfH |
? kJ/mol |
Standard molar entropy, S |
? J/(mol K) |
Heat capacity, cp | ? J/(mol K) |
Liquid properties | |
Std enthalpy change of formation, ΔfH |
? kJ/mol |
Standard molar entropy, S |
? J/(mol K) |
Heat capacity, cp | 80.80 J/(mol K) |
Gas properties | |
Std enthalpy change of formation, ΔfH |
−45.92 kJ/mol |
Std Gibbs free energy change of formation, ΔfG |
−16.6 kJ/mol |
Standard molar entropy, S |
192.77 J/(mol K) |
Heat capacity, cp | 35.06 J/(mol K) |
Heat capacity ratio, γ at 15 °C |
1.310 |
van der Waals' constants | a = 422.5 L2 kPa/mol2 b = 0.03707 L/mol |
P in mm Hg | 1 | 10 | 40 | 100 | 400 | 760 | 1520 | 3800 | 7600 | 15600 | 30400 | 45600 | |
T in °C | −109.1(s) | −91.9(s) | −79.2(s) | −68.4 | −45.4 | −33.6 | −18.7 | 4.7 | 25.7 | 50.1 | 78.9 | 98.3 |
Table data (above) obtained from CRC Handbook of Chemistry and Physics 44th ed. The (s) notation indicates equilibrium temperature of vapor over solid. Otherwise temperature is equilibrium of vapor over liquid.
Vapor-pressure formula for ammonia:[2]
where P is pressure in kPa, and T is temperature in kelvins;
|
|
UV-Vis | |
---|---|
λmax | None nm |
Extinction coefficient, ε | None |
IR | |
Major absorption bands | 3444, 3337, 1627, 950 cm−1 |
NMR | |
Proton NMR | |
Carbon-13 NMR | None – no carbons |
Other NMR data | |
MS | |
Masses of main fragments |
17 (100%) 16(80%) 15(9%) |
Regulatory data | |
---|---|
EINECS number | 231-635-3 (gas) 215-647-6 (soln.) |
EU index number | 007-001-00-5 (gas) 007-001-01-2 (soln.) |
PEL-TWA (OSHA) | 50 ppm (35 mg/m3) |
IDLH (NIOSH) | 300 ppm |
Flash point | 11 °C |
Autoignition temperature | 651 °C |
Explosive limits | 15–28% |
RTECS # | BO0875000 |
The handling of this chemical may incur notable safety precautions... It is highly recommend that you seek the Safety Data Sheet (SDS) for this chemical from a reliable source and follow its directions.