Silicon nitride
| Sintered silicon nitride ceramic | |
| Names | |
|---|---|
| Preferred IUPAC name Silicon nitride | |
| Other names Trisilicon tetranitride, Nierite | |
| Identifiers | |
| 3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.031.620 | 
| EC Number | 
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| MeSH | Silicon+nitride | 
| PubChem CID | |
| UNII | |
| CompTox Dashboard (EPA) | |
| 
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| 
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| Properties | |
| Si3N4 | |
| Molar mass | 140.283 g·mol−1 | 
| Appearance | grey, odorless powder | 
| Density | 3.17 g/cm3 | 
| Melting point | 1,900 °C (3,450 °F; 2,170 K) (decomposes) | 
| Insoluble | |
| Refractive index (nD) | 2.016 | 
| Thermochemistry | |
| Std molar entropy (S⦵298) | 101.3 J·mol−1·K−1 | 
| Std enthalpy of formation (ΔfH⦵298) | −743.5 kJ·mol−1 | 
| Gibbs free energy (ΔfG⦵) | −642.6 kJ·mol−1 | 
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
| Main hazards | |
| Related compounds | |
| Other anions | silicon carbide, silicon dioxide | 
| Other cations | boron nitride, carbon nitride | 
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references | |
Silicon nitride is a chemical compound of the elements silicon and nitrogen. Si
3N
4 (Trisilicon tetranitride) is the most thermodynamically stable and commercially important of the silicon nitrides, and the term ″Silicon nitride″ commonly refers to this specific composition. It is a white, high-melting-point solid that is relatively chemically inert, being attacked by dilute HF and hot H
3PO
4. It is very hard (8.5 on the mohs scale). It has a high thermal stability with strong optical nonlinearities for all-optical applications.