Element Silicon
It is a chemical element with the symbol Si and atomic number 14.
It is a hard and brittle crystalline solid with a blue-grey metallic lustre; and it is a tetravalent metalloid and semiconductor.
Element Silicon is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, and lead are below it
Names and Identifiers
| Chemical Formula: | Si |
| CAS: | 7440-21-3 |
| Molecular Weight: | 28.09000 g/mol |
| EC Number : | 231-130-8 |
| MDL Number: | MFCD00085311 |
| Color: | dark gray with a bluish tinge |
| Other Names: | Silicium, Silicio |
| PubChem CID: | 5461123 |
| IUPAC Name: | Silicon |
| Inchl: | InChI=1S/Si |
| InChI Key: | XUIMIQQOPSSXEZ-UHFFFAOYSA-N |
| Canonical SMILES: | [Si] |
| ICSC Number: | 1508 |
Physical & Chemical Properties
| Phase: | Solid |
| Density: | 2.3290 g/cm³ |
| Boiling Point: | 3538 K (3265 °C, 5909 °F) |
| Melting Point: | 1687 K (1414 °C, 2577 °F) |
| Molecular Formula: | Si |
| Flash Point: | n/a |
| Exact Mass: | 27.98000 |
| Symbol: |  |
| Signal Word: | Warning |
| Hazard Statements: | H228 |
| Precautionary Statements: | P210 |
| Hazard Codes: | F:Flammable |
| Risk Phrases: | R11 |
| Safety Phrases: | S16-S33-S7/9 |
| RIDADR: | UN 2922 8/PG 2 |
| WGK Germany: | 2 |
| RTECS: | VW0400000 |
| Packaging Group: | III |
| Hazard Class: | 4.1 |
Naturally occurring silicon is composed of three stable isotopes, 28Si (92.23%), 29Si (4.67%), and 30Si (3.10%).
Naturally occurring isotopes
| Isotope | Mass/Da | Natural abundance (atom %) | Nuclear spin (I) | Magnetic moment (μ/μN) |
|---|---|---|---|---|
| 28Si | 27.9769271 (7) | 92.2297 (7) | 0 | 0 |
| 29Si | 28.9764949 (7) | 4.6832 (5) | 1/2 | -0.55529 |
| 30Si | 29.9737707 (7) | 3.0872 (5) | 0 | 0 |
Radiosotope data
| Isotope | Mass/Da | Half-life | Mode of decay | Nuclear spin | Nuclear magnetic moment |
|---|---|---|---|---|---|
| 26Si | 25.992330 | 2.23 s | EC to 26Al | 0 | |
| 27Si | 26.9867041 | 4.14 s | EC to 27Al | 5/2 | |
| 31Si | 30.975362 | 2.62 h | β– to 31P | 3/2 | |
| 32Si | 31.974148 | 160 y | β– to 32P | 0 | |
| 33Si | 32.97800 | 6.1 s | β– to 33P | 3/2 | |
| 34Si | 33.97858 | 2.8 s | β– to 34P | 0 |