Silicon dioxide

Properties

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	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 naturally occurring oxide of silicon, chemical formula SiO₂.

It is found in nature in several forms, including sand and quartz and is also a major constituent of many minerals, including flint.

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.

Inhaling silica dust can lead to silicosis.