Silicon dioxide, commonly known as silica, is a naturally occurring compound found in quartz and sand. It is a primary component of most rocks and is widely used in various industries due to its high thermal stability, chemical inertness, and optical clarity. In chemical applications, it is valued for its abrasive, refractory, and adsorptive properties, making it essential in products like glass, ceramics, and electronics.
Description
Silicon dioxide CAS#7631-86-9
| Silicon dioxide Chemical Properties |
| Melting point | >1600???C(lit.) |
| Boiling point | >100???C(lit.) |
| density | 2.2-2.6?g/mL?at 25???C |
| vapor pressure | 13.3hPa at 1732?? |
| refractive index | 1.46 |
| Fp | 2230??C |
| storage temp. | 2-8??C |
| solubility | Practically insoluble in water and in mineral acids except hydrofluoric acid. It dissolves in hot solutions of alkali hydroxides. |
| form | suspension |
| pka | 6.65-9.8[at 20 ??] |
| Specific Gravity | 2.2 |
| color | White to yellow |
| PH | 5-8 (100g/l, H2O, 20??)(slurry) |
| Odor | at 100.00?%. odorless |
| Resistivity | 1??10*20 (??/?ฬฆ?.cm) |
| Water Solubility | insoluble |
| Hydrolytic Sensitivity | 6: forms irreversible hydrate |
| Sensitive | Hygroscopic |
| Crystal Structure | Trigonal |
| Merck | 14,8493 |
| Exposure limits | NIOSH: IDLH 3000 mg/m3; TWA 6 mg/m3 |
| Stability: | Stable. |
| CAS DataBase Reference | 7631-86-9(CAS DataBase Reference) |
| NIST Chemistry Reference | Silicon(iv) oxide(7631-86-9) |
| IARC | 3 (Vol. Sup 7, 68) 1997 |
| EPA Substance Registry System | Silica (7631-86-9) |
| Safety Information |
| Hazard Codes | Xn,Xi |
| Risk Statements | 36/37/38-36/37-22-43-52/53-36/38 |
| Safety Statements | 26-37/39-36-36/37/39-36/37-61 |
| OEB | B |
| OEL | TWA: 6 mg/m3 |
| HS Code | 2811221000 |
| Toxicity | LC inhalation in rat: > 200gm/m3/1H |
| IDLA | 3,000 mg/m3 |
