Silicon dioxide

Athanor · official

O₂Si · 60.084 g/mol

IUPAC name: dioxosilane

Also called silica, quartz, sand, E551, silicate, sodium silicate

Inorganic

Open in Athanor

Drawn from its SMILES with RDKit

WarningCauses skin irritation · Causes serious eye irritation · May cause respiratory irritation

Names and identifiers

IUPAC name: dioxosilane
Synonyms: silica, quartz, sand
+ 41 more
E551, silicate, sodium silicate, Silica, Dioxosilane, Silicic anhydride, Diatomaceous silica, Wessalon, Zorbax sil, Silica, amorphous, Silica, colloidal, Sillikolloid, Acticel, Carplex, Extrusil, Porasil, Santocel, Silikil, Siloxid, Sipernat, Neosil, Neosyl, Zipax, colloidal silica, White carbon, Silicone dioxide, Vulkasil S, Snowtex O, Corasil II, Cab-o-sil M-5, Tokusil TPLM, Dri-Die, Manosil vn 3, Ultrasil VH 3, Ultrasil VN 3, Aerosil K 7, Carplex 30, Carplex 80, Snowtex 30, Syton 2X, Zeofree 80
Molecular formula: O₂Si
Empirical formula: O₂Si
Molecular weight: 60.084 g/mol
Exact mass: 59.96676
CAS number: 7631-86-9
PubChem CID: 24261
Canonical SMILES: O=[Si]=O
Isomeric SMILES: O=[Si]=O
InChI: InChI=1S/O2Si/c1-3-2
InChIKey: VYPSYNLAJGMNEJ-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Amorphous powder[6]
12 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Transparent to gray, odorless powder. Irritating to the skin and eyes on contact. Inhalation will cause irritation in the respiratory tract. [Note: Amorphous silica is the non-crystalline form of SiO2.] [1] CAMEO Chemicals
– Dry Powder; Other Solid; Large Crystals; CBI [2] EPA Chemical Data Reporting (CDR)
– Dry Powder; Wet Solid; Other Solid; Large Crystals; CBI; Liquid [2] EPA Chemical Data Reporting (CDR)
– Dry Powder; Large Crystals; Dry Powder; Large Crystals; Wet Solid; Dry Powder; Liquid; Liquid; Large Crystals; Liquid; Liquid; Other Solid; Dry Powder; Other Solid; Dry Powder; Large Crystals; Liquid; Other Solid; Dry Powder; Large Crystals; Liquid; Wet Solid; Other Solid; Other Solid; Wet Solid; Large Crystals; Dry Powder; Wet Solid; Other Solid; Dry Powder; Wet Solid; Large Crystals; Other Solid; CBI [2] EPA Chemical Data Reporting (CDR)
– Liquid; Other Solid; Dry Powder [2] EPA Chemical Data Reporting (CDR)
– COLOURLESS OR WHITE CRYSTALS. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– Solid [4] Occupational Safety and Health Administration (OSHA)
– Transparent to gray, odorless powder. [Note: Amorphous silica is the non-crystalline form of SiO2.] [5] The National Institute for Occupational Safety and Health (NIOSH)
–shown Amorphous powder [6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. V3 3205
– Transparent to gray powder (Note: Amorphous silica is the non-crystalline form of O2Si). ... solid [6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases. U.S. Department of Health & Human Services, Public Health Service, Center for Disease Control & Prevention. DHHS (NIOSH) Publication No. 2001-145 (CD-ROM) August 2001.
– Silica gel is a coherent, rigid, continuous three-dimensional network of spherical particles of colloidal microporous silica. [6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
– Transparent crystals [6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. V3 3205
Odor: Odorless[6]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
–shown Odorless [6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases. U.S. Department of Health & Human Services, Public Health Service, Center for Disease Control & Prevention. DHHS (NIOSH) Publication No. 2001-145 (CD-ROM) August 2001.
– Odorless [6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases. U.S. Department of Health & Human Services, Public Health Service, Center for Disease Control & Prevention. DHHS (NIOSH) Publication No. 2001-145 (CD-ROM) August 2001.
Melting point: 1710 °C (3110 °F)[6]
6 values
3 of 5 sources agree on it (most common value).
Value As written Source
1710 °C 3110 °F (NIOSH, 2024) [1] CAMEO Chemicals
1710 °Cshown 3110 °F [6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases. U.S. Department of Health & Human Services, Public Health Service, Center for Disease Control & Prevention. DHHS (NIOSH) Publication No. 2001-145 (CD-ROM) August 2001.
1710 °C 1710 °C [6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. V3 3205
1713 °C 1713 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
1722 °C 1722 °C [7] PAC Chemical Database, U.S. Department of Energy
1710 °C 3110 °F [5] The National Institute for Occupational Safety and Health (NIOSH)
Boiling point: 2230 °C[3]
6 values
4 of 5 sources agree on it (most common value).
Value As written Source
2230 °C 4046 °F at 760 mmHg (NIOSH, 2024) [1] CAMEO Chemicals
2230 °C 4046 °F [6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases. U.S. Department of Health & Human Services, Public Health Service, Center for Disease Control & Prevention. DHHS (NIOSH) Publication No. 2001-145 (CD-ROM) August 2001.
2230 °C 2230 °C [6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. V3 3205
2230 °Cshown 2230 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
2950 °C 2950 °C @760 [mm Hg] [7] PAC Chemical Database, U.S. Department of Energy
2230 °C 4046 °F [5] The National Institute for Occupational Safety and Health (NIOSH)
Density: Density = 2.20 g/cm[6]
13 values
4 of 5 sources agree on it (most common value).
Value As written Source
– 2.2 (NIOSH, 2024) - Denser than water [1] CAMEO Chemicals
– 2.6 [6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. V3 3205
– density: 2.2-2.6 [6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 13th ed. New York, NY: John Wiley & Sons, Inc. 1997., p. 995
–shown Density = 2.20 g/cm [6] Hazardous Substances Data Bank (HSDB)cites Gerhartz, W. (exec ed.). Ullmann's Encyclopedia of Industrial Chemistry. 5th ed.Vol A1: Deerfield Beach, FL: VCH Publishers, 1985 to Present., p. VA12 (1989) 373
– Density = 2.648 /alpha-Quartz/ /from table/ [6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
– Density = 2.269 /alpha-Tridymite/ /from table/ [6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
– Density = 2.318 /alpha-Cristobalite/ /from table/ [6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
– Density = 2.909 /Coesite/ /from table/ [6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
– Density = 4.287 /Stishovite/ /from table/ [6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
– 2.3 g/cm³ [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– 2.334 @25 °C [7] PAC Chemical Database, U.S. Department of Energy
– 2.2 @25 °C [7] PAC Chemical Database, U.S. Department of Energy
– 2.20 [5] The National Institute for Occupational Safety and Health (NIOSH)
6 more values were reported but failed the checks (unreadable or out of range), so they are not shown.
Solubility in water: Solubility in water: none[3]
10 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– Insoluble (NIOSH, 2024) [1] CAMEO Chemicals
– The solubility of the various phases of silicas is very complex and depends upon several factors. Solubility increases with temperature and pH and is affected by the presence of trace metals. Particle size influences the rate of solubility. /Silica/ [6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
– Insoluble [6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases. U.S. Department of Health & Human Services, Public Health Service, Center for Disease Control & Prevention. DHHS (NIOSH) Publication No. 2001-145 (CD-ROM) August 2001.
– Silica is rather poorly soluble in water although solubility is higher for the amorphous than for the crystalline morphologies. ... The external amorphous layer in quartz is more soluble than the crystalline underlying core. [6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
– Practically insoluble in water or acids. Dissolves readily in HF, forming silicon tetrafluoride. [6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. V3 3205
– Soluble in hot potassium hydroxide and hot sodium hydroxide solutions. Insoluble in ethanol. [6] Hazardous Substances Data Bank (HSDB)cites Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.
– Silica is rather poorly soluble in water and solubility is lower for the crystalline than for the amorphous morphologies. ...Solubility increases with temperature and pH and is affected by the presence of trace metals. Particle size influences the rate of solubility. [6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
– The external amorphous layer in quartz (the Beilby layer) is more soluble than the crystalline underlying core. [6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
–shown Solubility in water: none [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– Insoluble [5] The National Institute for Occupational Safety and Health (NIOSH)
Vapor pressure: 10 mmHg @ 1732 °C[6]

Value	As written	Source
–	Transparent to gray, odorless powder. Irritating to the skin and eyes on contact. Inhalation will cause irritation in the respiratory tract. [Note: Amorphous silica is the non-crystalline form of SiO2.]	[1] CAMEO Chemicals
–	Dry Powder; Other Solid; Large Crystals; CBI	[2] EPA Chemical Data Reporting (CDR)
–	Dry Powder; Wet Solid; Other Solid; Large Crystals; CBI; Liquid	[2] EPA Chemical Data Reporting (CDR)
–	Dry Powder; Large Crystals; Dry Powder; Large Crystals; Wet Solid; Dry Powder; Liquid; Liquid; Large Crystals; Liquid; Liquid; Other Solid; Dry Powder; Other Solid; Dry Powder; Large Crystals; Liquid; Other Solid; Dry Powder; Large Crystals; Liquid; Wet Solid; Other Solid; Other Solid; Wet Solid; Large Crystals; Dry Powder; Wet Solid; Other Solid; Dry Powder; Wet Solid; Large Crystals; Other Solid; CBI	[2] EPA Chemical Data Reporting (CDR)
–	Liquid; Other Solid; Dry Powder	[2] EPA Chemical Data Reporting (CDR)
–	COLOURLESS OR WHITE CRYSTALS.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Solid	[4] Occupational Safety and Health Administration (OSHA)
–	Transparent to gray, odorless powder. [Note: Amorphous silica is the non-crystalline form of SiO2.]	[5] The National Institute for Occupational Safety and Health (NIOSH)
–shown	Amorphous powder	[6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. V3 3205
–	Transparent to gray powder (Note: Amorphous silica is the non-crystalline form of O2Si). ... solid	[6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases. U.S. Department of Health & Human Services, Public Health Service, Center for Disease Control & Prevention. DHHS (NIOSH) Publication No. 2001-145 (CD-ROM) August 2001.
–	Silica gel is a coherent, rigid, continuous three-dimensional network of spherical particles of colloidal microporous silica.	[6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
–	Transparent crystals	[6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. V3 3205

Value	As written	Source
–shown	Odorless	[6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases. U.S. Department of Health & Human Services, Public Health Service, Center for Disease Control & Prevention. DHHS (NIOSH) Publication No. 2001-145 (CD-ROM) August 2001.
–	Odorless	[6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases. U.S. Department of Health & Human Services, Public Health Service, Center for Disease Control & Prevention. DHHS (NIOSH) Publication No. 2001-145 (CD-ROM) August 2001.

Value	As written	Source
1710 °C	3110 °F (NIOSH, 2024)	[1] CAMEO Chemicals
1710 °Cshown	3110 °F	[6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases. U.S. Department of Health & Human Services, Public Health Service, Center for Disease Control & Prevention. DHHS (NIOSH) Publication No. 2001-145 (CD-ROM) August 2001.
1710 °C	1710 °C	[6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. V3 3205
1713 °C	1713 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
1722 °C	1722 °C	[7] PAC Chemical Database, U.S. Department of Energy
1710 °C	3110 °F	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
2230 °C	4046 °F at 760 mmHg (NIOSH, 2024)	[1] CAMEO Chemicals
2230 °C	4046 °F	[6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases. U.S. Department of Health & Human Services, Public Health Service, Center for Disease Control & Prevention. DHHS (NIOSH) Publication No. 2001-145 (CD-ROM) August 2001.
2230 °C	2230 °C	[6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. V3 3205
2230 °Cshown	2230 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
2950 °C	2950 °C @760 [mm Hg]	[7] PAC Chemical Database, U.S. Department of Energy
2230 °C	4046 °F	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	2.2 (NIOSH, 2024) - Denser than water	[1] CAMEO Chemicals
–	2.6	[6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. V3 3205
–	density: 2.2-2.6	[6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J., Sr (Ed.). Hawley's Condensed Chemical Dictionary. 13th ed. New York, NY: John Wiley & Sons, Inc. 1997., p. 995
–shown	Density = 2.20 g/cm	[6] Hazardous Substances Data Bank (HSDB)cites Gerhartz, W. (exec ed.). Ullmann's Encyclopedia of Industrial Chemistry. 5th ed.Vol A1: Deerfield Beach, FL: VCH Publishers, 1985 to Present., p. VA12 (1989) 373
–	Density = 2.648 /alpha-Quartz/ /from table/	[6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
–	Density = 2.269 /alpha-Tridymite/ /from table/	[6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
–	Density = 2.318 /alpha-Cristobalite/ /from table/	[6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
–	Density = 2.909 /Coesite/ /from table/	[6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
–	Density = 4.287 /Stishovite/ /from table/	[6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
–	2.3 g/cm³	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	2.334 @25 °C	[7] PAC Chemical Database, U.S. Department of Energy
–	2.2 @25 °C	[7] PAC Chemical Database, U.S. Department of Energy
–	2.20	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	Insoluble (NIOSH, 2024)	[1] CAMEO Chemicals
–	The solubility of the various phases of silicas is very complex and depends upon several factors. Solubility increases with temperature and pH and is affected by the presence of trace metals. Particle size influences the rate of solubility. /Silica/	[6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
–	Insoluble	[6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards & Other Databases. U.S. Department of Health & Human Services, Public Health Service, Center for Disease Control & Prevention. DHHS (NIOSH) Publication No. 2001-145 (CD-ROM) August 2001.
–	Silica is rather poorly soluble in water although solubility is higher for the amorphous than for the crystalline morphologies. ... The external amorphous layer in quartz is more soluble than the crystalline underlying core.	[6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
–	Practically insoluble in water or acids. Dissolves readily in HF, forming silicon tetrafluoride.	[6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. V3 3205
–	Soluble in hot potassium hydroxide and hot sodium hydroxide solutions. Insoluble in ethanol.	[6] Hazardous Substances Data Bank (HSDB)cites Hartley, D. and H. Kidd (eds.). The Agrochemicals Handbook. 2nd ed. Lechworth, Herts, England: The Royal Society of Chemistry, 1987.
–	Silica is rather poorly soluble in water and solubility is lower for the crystalline than for the amorphous morphologies. ...Solubility increases with temperature and pH and is affected by the presence of trace metals. Particle size influences the rate of solubility.	[6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
–	The external amorphous layer in quartz (the Beilby layer) is more soluble than the crystalline underlying core.	[6] Hazardous Substances Data Bank (HSDB)cites IARC. Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans. Geneva: World Health Organization, International Agency for Research on Cancer, 1972-PRESENT. (Multivolume work).
–shown	Solubility in water: none	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Insoluble	[5] The National Institute for Occupational Safety and Health (NIOSH)

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 3
Rings: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0
H-bond donors: 0
H-bond acceptors: 2
Rotatable bonds: 0
TPSA (Å²): 34.1
Formal charge: 0
Complexity: 18 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: D∞h of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

O53.26%
Si46.74%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: -0.62 Crippen (Wildman and Crippen 1999)
log S (water solubility): 0.18 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 5.27 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 60.08
log P ≤ 5 (Crippen): -0.62
H-bond donors ≤ 5: 0
H-bond acceptors ≤ 10: 2

Passes all four rules.

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Warning

Most widely reported: 2,540 company reports to ECHA. Source [8].

Harmful or irritant

H315Causes skin irritation (56.3% of reports)
H319Causes serious eye irritation (56.3% of reports)
H335May cause respiratory irritation (56.3% of reports)

Precautionary statements: P261, P264, P264+P265, P271, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P337+P317, P362+P364, P403+P233, P405, P501

View all classifications (9)

[8] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 35% (889 of 2540) of reports.
[8] European Chemicals Agency (ECHA) · 2,540 reports · WarningH315, H319, H335
[8] European Chemicals Agency (ECHA) · 1,682 reportsThis chemical does not meet GHS hazard criteria for 96% (1614 of 1682) of all reports.
[8] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 9.7% (125 of 1288) of reports.
[8] European Chemicals Agency (ECHA) · 1,288 reports · DangerH350, H372, H373
[8] European Chemicals Agency (ECHA) · 1,124 reportsThis chemical does not meet GHS hazard criteria for 96.6% (1086 of 1124) of all reports.
[8] European Chemicals Agency (ECHA) · 17 reportsThis chemical does not meet GHS hazard criteria for 100% (17 of 17) of all reports.
[8] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 83.3% (5 of 6) of all reports.
[8] European Chemicals Agency (ECHA) · 6 reports · WarningH315, H319, H335

Exposure limits

PEL-TWA (8-Hour Time Weighted Average): 5 mg/m³ (as PNOR, respirable dust)[4]
PEL: TWA 20 mppcf (80 mg/m3/%SiO2) See Appendix C (Mineral Dusts) See Appendix G[5]
REL: TWA 6 mg/m3[5]
TLV: (respirable fraction): 0.025 mg/m[3]
IDLH: 3000 mg/m3 (NIOSH, 2024)[1]
IDLH: 3000 mg/cu m[6]

First aid

Excerpt from NIOSH Pocket Guide for Silica, amorphous: Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Breathing: Fresh AIR - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. Other measures are usually unnecessary. (NIOSH, 2024)[1]
(General first aid procedures) Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Breathing: Fresh air[5]
Fresh air, rest.[3]
Rinse and then wash skin with water and soap.[3]

Storage

Separated from strong oxidants.[3]
Avoid dusty atmosphere. (cab-O-Sil*)[6]
Precautions FOR "carcinogens": Storage site should be as close as practical to lab in which carcinogens are to be used, so that only small quantities required for ... Expt need to be carried. Carcinogens should be kept in only one section of cupboard, an explosion-proof refrigerator or freezer (depending on chemicophysical properties ...) that bears appropriate label. An inventory ... Should be kept, showing quantity of carcinogen & date it was acquired ... Facilities for dispensing ... Should be contiguous to storage area. (chemical Carcinogens)[6]

Incompatibilities

Fluoride, oxygen difluoride, chlorine trifluoride.[6]
Vinyl acetate vapor may react vigorously in contact with silica gel... . (silica gel)[6]
Silica is attacked by alkaline aqueous solutions, by hydrofluoric acid and by catechol. The rates of etching in hydrofluoric acid vary in the following sequence: Stishovite < coesite < quartz < tridymite, cristobalite < vitreous silica.[6]
Etching in hydrofluoric acid eliminates the Beilby layer on quartz. Stishovite is almost insoluble in hydrofluoric acid and coesite reacts at a much lower rate than quartz or vitreous silica. Hydrofluoric acid solutions can thus be used to separate the various polymorphs.[6]

Safety data sheets on the supplier’s page: Sigma-Aldrich, Molport, MP Biomedicals.

Always read the supplier’s safety data sheet before working with it.

Spectra

FTIRSpectraBase (KBr pellet)
ATR-IRSpectraBase
RamanRRUFF Project · RRUFF Project · RRUFF Project · RRUFF Project · RRUFF Project · RRUFF Project

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[3]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[4]Occupational Safety and Health Administration (OSHA) · Public domain (US DOL) · via PubChem · retrieved 2026-10-14
[5]The National Institute for Occupational Safety and Health (NIOSH) · Public domain (US CDC) · via PubChem · retrieved 2026-10-14
[6]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[7]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[8]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[9]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[10]RRUFF Project · Linked only · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.