Calcium silicate

Calcium silicate

Names
Preferred IUPAC name Calcium silicate
Systematic IUPAC name Dicalcium silicate
Other names Belite Calcium monosilicate Calcium hydrosilicate Calcium metasilicate, Calcium orthosilicate Grammite Micro-cell Silene Silicic acid calcium salt
Identifiers
CAS Number	1344-95-2 Y 111811-33-7 hydrate Y 12168-85-3 calcium oxide Y
3D model (Jmol)	Interactive image
ChemSpider	14235 N 23811 calcium oxide Y
ECHA InfoCard	100.014.282
EC Number	235-336-9
E number	E552 (acidity regulators, ...)
KEGG	D03309 N
MeSH	Calcium+silicate
PubChem	14941 44154858 hydrate 25523 calcium oxide
UNII	S4255P4G5M Y
InChI InChI=1S/2Ca.O4Si/c;;1-5(2,3)4/q2*+2;-4 N Key: JHLNERQLKQQLRZ-UHFFFAOYSA-N N
SMILES [Ca++].[Ca++].[O-][Si]([O-])([O-])[O-]
Properties
Chemical formula	Ca2O4Si
Molar mass	172.24 g·mol−1
Appearance	White crystals
Density	0.29 g/cm3 (solid)
Melting point	1,540 °C (2,800 °F; 1,810 K)
Solubility in water	0.01% (20 °C)
Thermochemistry
Std molar entropy (So298)	84 J·mol−1·K−1
Std enthalpy of formation (ΔfHo298)	−1630 kJ·mol−1
Pharmacology
ATC code	A02AC02 (WHO)
Hazards
Main hazards	Irritant
Safety data sheet
NFPA 704	0 2 0
Flash point	Not applicable
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp)
REL (Recommended)	TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)
IDLH (Immediate danger)	N.D.
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Calcium monosilicate
Calcium hydrosilicate
Calcium metasilicate, Calcium orthosilicate
Grammite
Micro-cell
Silene

Calcium silicate (often referred to by its shortened trade name Cal-Sil or Calsil) is the chemical compound Ca₂SiO₄, also known as calcium orthosilicate and sometimes formulated 2CaO.SiO₂. It is one of a group of compounds obtained by reacting calcium oxide and silica in various ratios e.g. 3CaO•SiO₂, Ca₃SiO₅; 2CaO•SiO₂, Ca₂SiO₄; 3CaO•2SiO₂, Ca₃Si₂O₇ and CaO•SiO₂, CaSiO₃. Calcium silicate is a white free-flowing powder derived from limestone and diatomaceous earth. It has a low bulk density and high physical water absorption. It is used in roads, insulation, bricks, roof tiles, table salt and occurs in cements, where it is known as belite (or in cement chemist notation C₂S).

It is used as an anti-caking agent in food preparation and an antacid. It is approved by the United Nations' FAO and WHO bodies as a safe food additive in a large variety of products.

Calcium silicate is commonly used as a safe alternative to asbestos for high temperature insulation materials. Industrial grade piping and equipment insulation is often fabricated from calcium silicate. Its fabrication is a routine part of the curriculum for insulation apprentices. Calcium silicate competes in these realms against rockwool as well as proprietary insulation solids, such as perlite mixture and vermiculite bonded with sodium silicate. Although it is popularly considered an asbestos substitute, early uses of calcium silicate for insulation still made use of asbestos fibers.