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| General | |
|---|---|
| Name | Silicon dioxide |
| Chemical formula | SiO2 |
| Appearance | Transparent solid |
| Physical | |
| Formula weight | 60.1 amu |
| Melting point | 1986 K (1713 °C) |
| Boiling point | 2503 K (2230 °C) |
| Density | 2.6 ×103 kg/m3 |
| Crystal structure | Quartz, cristobalite or tridymite |
| Solubility | 0.012 g in 100g water |
| Thermochemistry | |
| ΔfH0gas | -305.43 kJ/mol |
| ΔfH0liquid | -899.86 kJ/mol |
| ΔfH0solid | -910.86 kJ/mol |
| S0gas, 1 bar | 228.98 J/mol·K |
| S0liquid, 1 bar | ? J/mol·K |
| S0solid | 41.46 J/mol·K |
| Safety | |
| Ingestion | Low hazard. |
| Inhalation | Irritation, long term exposure causes silicosis. |
| Skin | May cause irritation. |
| Eyes | May cause irritation. |
| More info | |
| SI units were used where possible. Unless otherwise stated, standard conditions were used. | |
The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2.
It is found in nature in several forms, including quartz and opal. Also, Horsetail is one of the plants which is rich in Silica.
It is manufactured in several forms including glass (in colorless high purity form called fused silica) and silica gel (used e.g. as desiccants in brand new clothes and leather goods). Silica is a major ingredient of Portland cement. The ceramic re-entry heat protection tiles mounted on the bottom side of the Space Shuttles are made mostly of silica.
Inhaling silica dust can lead to silicosis.
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