Lithium nitride is a compound with the formula Li3N. It is the only stable alkali metal nitride. The solid has a reddish-pink color and high melting point.[1]
Crystal structure of lithium nitride.
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Names | |
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Preferred IUPAC name
Lithium nitride | |
Other names
Trilithium nitride
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Identifiers | |
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3D model (JSmol)
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ChEBI |
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ChemSpider |
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ECHA InfoCard | 100.043.144 |
EC Number |
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1156 | |
PubChem CID
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CompTox Dashboard (EPA)
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Properties | |
Li3N | |
Molar mass | 34.83 g/mol |
Appearance | red, purple solid |
Density | 1.270 g/cm3 |
Melting point | 813 °C (1,495 °F; 1,086 K) |
reacts | |
log P | 3.24 |
Structure | |
see text | |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards
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reacts with water to release ammonia |
GHS labelling: | |
Danger | |
H260, H314 | |
P223, P231+P232, P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P335+P334, P363, P370+P378, P402+P404, P405, P501 | |
NFPA 704 (fire diamond) | |
Related compounds | |
Other anions
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Lithium oxide |
Other cations
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Sodium nitride Potassium nitride |
Related compounds
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Lithium amide Lithium imide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
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Lithium nitride is prepared by direct combination of elemental lithium with nitrogen gas:[2]
Instead of burning lithium metal in an atmosphere of nitrogen, a solution of lithium in liquid sodium metal can be treated with N2.
Lithium nitride reacts violently with water to produce ammonia:
alpha-Li3N (stable at room temperature and pressure) has an unusual crystal structure that consists of two types of layers, one sheet has the composition Li2N− contains 6-coordinate N centers and the other sheet consists only of lithium cations.[3] Two other forms are known: beta-Lithium nitride, formed from the alpha phase at 4,200 bars (4,100 atm) has the sodium arsenide (Na3As) structure; gamma-Lithium nitride (same structure as Li3Bi) forms from the beta form at 35 to 45 gigapascals (350,000 to 440,000 atm).[4]
Lithium nitride shows ionic conductivity for Li+, with a value of c. 2×10−4Ω−1cm−1, and an (intracrystal) activation energy of c. 0.26eV (c. 24 kJ/mol). Hydrogen doping increases conductivity, whilst doping with metal ions (Al, Cu, Mg) reduces it.[5][6] The activation energy for lithium transfer across lithium nitride crystals (intercrystalline) has been determined to be higher at c. 68.5 kJ/mol.[7] The alpha form is a semiconductor with band gap of c. 2.1 eV.[4]
Reaction with hydrogen at under 300 °C (0.5 MPa pressure) produces lithium hydride and lithium amide.[8]
Lithium nitride has been investigated as a storage medium for hydrogen gas, as the reaction is reversible at 270 °C. Up to 11.5% by weight absorption of hydrogen has been achieved.[9]
Reacting lithium nitride with carbon dioxide results in amorphous carbon nitride (C3N4), a semiconductor, and lithium cyanamide (Li2CN2), a precursor to fertilizers, in an exothermic reaction.[10] [11]