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Encyclopedia > Silicon dioxide
Silicon dioxide
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General
Other names Silica, Quartz, sand
see text
Molecular formula SiO2
Molar mass 60.1 g/mol
Appearance white powdery substance
solid (when pure)
CAS number 7631-86-9
Properties
Density and phase 2.2 g/cm³, solid
Solubility in water 0.012 g in 100g of water
Melting point 1650 (±75) °C
Boiling point 2230 °C
Structure
Coordination
geometry
tetrahedral
Crystal structure various
Hazards
MSDS External MSDS
EU classification  
NFPA 704
0
0
0
R-phrases R42 R43 R49
S-phrases S22 S36 S37 S45 S53
Flash point non-flammable
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Related compounds
Other anions Silicon sulfide
Other cations Carbon dioxide
Germanium dioxide
Tin(IV) oxide
Lead(IV) oxide
Related compounds Silicic acid
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references


The chemical compound silicon dioxide, also known as silica or silox (from the Latin "silex"), is the oxide of silicon, chemical formula SiO2, and has been known for its hardness since the 16th century. It is a principal component of most types of glass and substances such as concrete. Image File history File linksMetadata Download high-resolution version (2048x1360, 1191 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Silicon dioxide Metadata This file contains additional information, probably added from the digital camera or scanner used to... This article or section does not cite any references or sources. ... This article does not cite any references or sources. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... In physics, density is mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: ρ (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ... Italic text This article is about the boiling point of liquids. ... The coordination geometry of an atom is the geometrical pattern formed by its neighbors in a molecule or a crystal. ... A tetrahedron (plural: tetrahedra) is a polyhedron composed of four triangular faces, three of which meet at each vertex. ... Enargite crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... An example MSDS in a US format provides guidance for handling a hazardous substance and information on its composition and properties. ... Council Directive 67/548/EEC of 27 June 1967 on the approximation of laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances (as amended) is the main European Union law concerning chemical safety. ... NFPA 704 is a standard maintained by the U.S. National Fire Protection Association. ... Image File history File links NFPA_704. ... R-phrases are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations. ... S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. ... For other uses, see Flash point (disambiguation). ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... The relative dielectric constant of a material under given conditions is a measure of the extent to which it concentrates electrostatic lines of flux. ... Ultraviolet-Visible Spectroscopy or Ultraviolet-Visible Spectrophotometry (UV/ VIS) involves the spectroscopy of photons (spectrophotometry). ... Infrared spectroscopy (IR Spectroscopy) is the subset of spectroscopy that deals with the IR region of the EM spectrum. ... It has been suggested that NMR Data Processing be merged into this article or section. ... Mass spectrometry (also known as mass spectroscopy (deprecated)[1] or informally, mass-spec and MS) is an analytical technique used to measure the mass-to-charge ratio of ions. ... This article is about the electrically charged particle. ... Silicon sulfide refers to the chemical compound with the formula SiS2. ... This article is about the electrically charged particle. ... In order to meet Wikipedias quality standards, this article requires cleanup. ... Germanium dioxide, also called germanium oxide and germania, is an inorganic compound, an oxide of germanium. ... Tin dioxide, SnO2, also stannic oxide, is an oxide of tin, with tin in oxidation state +4. ... Lead dioxide, PbO2, also plumbic oxide, is an oxide of lead, with lead in oxidation state +4. ... Silicic acid is a general name for a family of chemical compounds of silicon, hydrogen, and oxygen, with the general formula [SiOx(OH)4-2x]n. ... In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals) and 25 degrees Celsius (298. ... A chemical compound is a chemical substance of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition. ... For other uses, see Latin (disambiguation). ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance dark gray, bluish tinge Atomic mass 28. ... An oxide is a chemical compound containing an oxygen atom and other elements. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance as coarse powder, dark grey with bluish tinge Standard atomic weight 28. ... This article or section does not cite any references or sources. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance as coarse powder, dark grey with bluish tinge Standard atomic weight 28. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... This article is about the material. ... This article is about the construction material. ...


Siliceous is an adjective meaning "related to silica".

Contents

Manufactured forms

Silica is manufactured in several forms including:

It is used in the production of various products. This article is about the material. ... Fused quartz is a man-made material manufactured principally from sands. ... Beads of silica gel Silica gel is a granular, porous form of silica made synthetically from sodium silicate. ... A dessicant is a hygroscopic substance that induces or sustains a state of dryness (desiccation) in its local vicinity in a moderately-well sealed container. ...

  • Inexpensive soda-lime glass is the most common and typically found in drinking glasses, bottles, and windows.
  • A raw material for many whiteware ceramics such as earthenware, stoneware and porcelain.
  • A raw material for the production of Portland cement.
  • A food additive, primarily as a flow agent in powdered foods, or to absorb water (see the ingredients list for).
  • The natural ("native") oxide coating that grows on silicon is hugely beneficial in microelectronics. It is a superior electric insulator, possessing high chemical stability. In electrical applications, it can protect the silicon, store charge, block current, and even act as a controlled pathway to allow small currents to flow through a device. At room temperature, however, it grows extremely slowly, and so to manufacture such oxide layers on silicon, the traditional method has been the deliberate heating of silicon in high temperature furnaces within an oxygen ambient (thermal oxidation).
  • Raw material for aerogel in the Stardust spacecraft
  • Used in the extraction of DNA and RNA due to its ability to bind to the nucleic acids under the presence of chaotropes.
  • Added to medicinal anti-foaming agent, like Simethicone, with a small portion to enhance defoaming activity.

Soda-lime glass is the kind of glass which is most widely used for various purposes. ... Earthenware is a common ceramic material, which is used extensively for pottery tableware and decorative objects. ... A Staffordshire stoneware plate from the 1850s with transferred copper print - (From the home of JL Runeberg) Stoneware is a category of clay and a type of ceramic distinguished primarily by its firing and maturation temperature (from about 1200°C to 1315 °C). ... “Fine China” redirects here. ... Sampling fast set Portland cement Portland cement is the most common type of cement in general usage, as it is a basic ingredient of concrete, mortar and plaster. ... Food additives are substances added to food to preserve flavor or improve its taste and appearance. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance as coarse powder, dark grey with bluish tinge Standard atomic weight 28. ... Microelectronics is a subfield of electronics. ... This article or section is in need of attention from an expert on the subject. ... In microfabrication, thermal oxidation is a way to produce a thin layer of oxide (usually silicon dioxide) on the surface of a wafer (semiconductor). ... This article or section is in need of attention from an expert on the subject. ... An artists rendering of Stardust (NASA image) The Stardust capsule with cometary and interstellar samples landed at the U.S. Air Force Utah Test and Training Range at 10:10 UTC (15 January 2006) in the Bonneville Salt Flats. ... A Chaotropic agent is an agent which causes molecular structure to be disrupted; in particular, those formed by nonbonding forces such as hydrogen bonding, Van der Waals interactions, and the hydrophobic effect. ... An antifoaming agent is a food ingredient intended to curb effusion or effervescence in preparation or serving. ... Simethicone, is an oral anti-foaming agent used to reduce bloating, discomfort and pain caused by excess gas in the stomach or intestinal tract. ...

Health effects

Manufactured silica fume at maximum surface area of 380m²/g
Manufactured silica fume at maximum surface area of 380m²/g

Inhaling finely divided crystalline silica dust in significant quantities can lead to silicosis or (much more rarely) cancer, as the dust becomes lodged in the lungs and continuously irritates them (silica does not dissolve over time). This effect can be an occupational hazard for people working with sandblasting equipment, products that contain powdered silica, and so on. Image File history File links Size of this preview: 450 × 600 pixel Image in higher resolution (960 × 1280 pixel, file size: 132 KB, MIME type: image/jpeg) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Silicon dioxide Silicone... Image File history File links Size of this preview: 450 × 600 pixel Image in higher resolution (960 × 1280 pixel, file size: 132 KB, MIME type: image/jpeg) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Silicon dioxide Silicone... Silicosis (also known as Grinders disease) is a form of pneumoconiosis caused by inhalation of crystalline silica dust, and is marked by inflammation and scarring in forms of nodular lesions in the upper lobes of the lungs. ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... Man sandblasting a stone wall Device used for adding sand to the compressed air (top of which is a sieve for adding the sand) Diesel powered compressor used as an air supply for sandbasting Sandblasting or bead blasting[1] is a generic term for the process of smoothing, shaping and...


In all other respects, silicon dioxide is inert and harmless. When silica is ingested orally, it passes unchanged through the gastrointestinal tract, exiting in the feces, leaving no trace behind. Small pieces of silicon dioxide are equally harmless, as long as they are not large enough to mechanically obstruct the GI tract, or jagged enough to lacerate its lining. Silicon dioxide produces no fumes and is insoluble in vivo. It is indigestible, with zero nutritional value and zero toxicity. Horse feces Feces, faeces, or fæces (see spelling differences) is a waste product from an animals digestive tract expelled through the anus (or cloaca) during defecation. ...


Chemistry

Silicon dioxide is formed when silicon is exposed to oxygen (or air). A very thin layer (approximately 1 nm or 10 Å) of so-called 'native oxide' is formed on the surface when silicon is exposed to air under ambient conditions. Higher temperatures and alternate environments are used to grow well-controlled layers of silicon dioxide on silicon. A nanometre (American spelling: nanometer, symbol nm) is a unit of length in the metric system, equal to one thousand-millionth of a metre, which is the current SI base unit of length. ... An Ã¥ngström or aangstroem (the official transliteration), or angstrom (symbol Ã…) is a non-SI unit of length that is internationally recognized, equal to 0. ...


Silicon dioxide has covalent bonding and forms a network structure (also known as lattice or continuous). Covalent bonding is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms, or sometimes between atoms and other covalent bonds. ... Enargite crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ...


Silicon dioxide is attacked by hydrofluoric acid (HF). HF is used to remove or pattern silicon dioxide in the semiconductor industry. Hydrofluoric acid is a solution of hydrogen fluoride in water. ...


References

  • R. K. Iler, The Chemistry of Silica (ISBN 0-471-02404-X)

See also

General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance as coarse powder, dark grey with bluish tinge Standard atomic weight 28. ... Amorphous carbonia, also called a-carbonia or a-CO2, is an exotic amorphous solid form of carbon dioxide that is analogous to amorphous silica glass. ... Fused quartz is a man-made material manufactured principally from sands. ... Quartz (from German Quarz[1]) is the second most common mineral in the Earths continental crust. ... This article is about the material. ... For other uses, see Sand (disambiguation). ... Silicon carbide (SiC) is a ceramic compound of silicon and carbon that is manufactured on a large scale for use mainly as an abrasive but also occurs in nature as the extremely rare mineral moissanite. ... Characteristics of mesoporous silica (SiO2): - The matrix is made of amorphous silica - Pores of 2 – 50 nm with narrow size distribution - Pores are ordered (e. ...

External links


  Results from FactBites:
 
Silicon - MSN Encarta (786 words)
Silicon is prepared as a brown amorphous powder or as gray-fl crystals.
Silicon dioxide is the principal constituent of sand.
Silicon is a semiconductor, in which the resistivity to the flow of electricity at room temperature is in the range between that of metals and that of insulators.
Silicon - ninemsn Encarta (792 words)
Silicon is in group 14 (or IVa) of the periodic table.
Silicon is prepared as a brown amorphous powder or as grey-fl crystals.
The silicates (such as the complex aluminium, calcium, and magnesium silicates) are the chief constituents of clays, soils, and rocks in the form of feldspars, amphiboles, pyroxenes, micas, and zeolites, and of semi-precious stones, such as olivine, garnet, zircon, topaz, and tourmaline.
  More results at FactBites »

 
 

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