Wiki Article
Sodium nitride
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| Names | |
|---|---|
| IUPAC name
Sodium nitride
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| Identifiers | |
3D model (JSmol)
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|
| ECHA InfoCard | 100.032.017 |
| EC Number |
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| Properties | |
| Na3N | |
| Molar mass | 82.976 g/mol |
| Appearance | reddish brown or dark blue solid |
| Melting point | 104 °C (219 °F; 377 K)[1] (decomposes) |
| reacts | |
| Structure | |
| Cubic, cP4[2] | |
| Pm3m[2] | |
| Thermochemistry | |
Std enthalpy of
formation (ΔfH⦵298) |
-151 J/mol[2] |
| Related compounds | |
Other anions
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Sodium amide Sodium imide |
Other cations
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Lithium nitride Potassium nitride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Sodium nitride is the inorganic compound with the chemical formula Na3N. In contrast to lithium nitride and some other nitrides, sodium nitride is unstable. It readily decomposes into its elements:[3]
- 2 Na3N → 6 Na + N2
It can be generated by various methods. The instability of sodium nitride is relevant to the mechanism of action of sodium azide in airbags:
- 2 NaN3N → 2 Na + 3 N2
Synthesis
[edit]It can be generated by combining atomic beams of sodium and nitrogen deposited onto a low-temperature sapphire substrate[3] or a metal surface. This synthesis can be further facilitated by introducing liquid Na-K alloy to the compound with the excess liquid removed and washed with fresh alloy. The solid is then separated from the liquid using a centrifuge. However Vajenine’s method is very air-sensitive and can decompose and combust rapidly, so an argon environment is used.[1]
Sodium nitride can be generated also by the thermal decomposition of NaNH2.[2]
Characteristics
[edit]Sodium nitride can be of reddish brown or dark blue color depending on the synthetic method.[3][1] It shows no signs of decomposition after several weeks when at room temperature.[1] The compound does not have a melting point as it decomposes back into its elemental forms as demonstrated using mass spectrometry around 360 K.[3][2] The estimated enthalpy of formation for the compound is +64 kJ/mol.[1]
Structure
[edit]Sodium nitride seems to be about 90% ionic at room temperature, but has the band gap typical for a semiconductor.[2][1] It adopts the anti-ReO3 structure with a simple lattice made up of NNa6 octahedra.[3][2][1][4] The compound has N−Na bond lengths of 236.6 pm.[3][1] This structure has been confirmed through X-ray diffraction and more recently neutron diffraction on powder and single crystals.[3][2][1][4]
References
[edit]- ^ a b c d e f g h i Vajenine, G.V. (2007). "Plasma-Assisted Synthesis and Properties of Na3N". Inorganic Chemistry. 46 (13): 5146–5148. doi:10.1021/ic700406q. PMID 17530752.
- ^ a b c d e f g h Sangster, J. (2004). "N-Na(Nitrogen-Sodium) System". Journal of Phase Equilibria and Diffusion. 25 (6): 560–563. Bibcode:2004JPED...25..560S. doi:10.1007/s11669-004-0082-0. S2CID 97905377.
- ^ a b c d e f g Fischer, D., Jansen, M. (2002). "Synthesis and structure of Na3N". Angew Chem. 41 (10): 1755–1756. doi:10.1002/1521-3773(20020517)41:10<1755::AID-ANIE1755>3.0.CO;2-C. PMID 19750706.
{{cite journal}}: CS1 maint: multiple names: authors list (link) Fischer, D.; Cancarevic, Z.; Schön, J. C.; Jansen, M. Z. (2004). "Synthesis and structure of K3N". Z. Anorg. Allg. Chem. 630 (1): 156. doi:10.1002/zaac.200300280.. 'Elusive Binary Compound Prepared' Chemical & Engineering News 80 No. 20 (20 May 2002) - ^ a b Vajenine, G. V., Hoch, C., Dinnebier, R. E., Senyshyn, A., Niewa, R. (2009). "A Temperature-dependent Structural Study of anti-ReO3-type Na3N: to Distort or not to Distort?". Zeitschrift für Anorganische und Allgemeine Chemie. 636 (1): 94–99. doi:10.1002/zaac.200900488.
{{cite journal}}: CS1 maint: multiple names: authors list (link)