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Silica

**Properties**
General
Name	Silicon dioxide
Chemical formula	Si O₂
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
Δ_fH⁰_gas	-305.43 kJ/mol
Δ_fH⁰_liquid	-899.86 kJ/mol
Δ_fH⁰_solid	-910.86 kJ/mol
S⁰_{gas, 1 bar}	228.98 J/mol·K
S⁰_{liquid, 1 bar}	? J/mol·K
S⁰_solid	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	Hazardous Chemical Database
SI units were used where possible. Unless otherwise stated, standard conditions were used. Disclaimer and references

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.

It is also manufactured in several forms including glass (in colorless high purity form called fused silica) and silica gel. It is a major ingredient of Portland cement. Also, Horsetail is one of the plant which is rich in Silica.

Inhaling silica dust can lead to silicosis.

Referenced By

Monazite

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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Silica".