Sodium aluminosilicate refers to compounds which contain
sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...
,
aluminium
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It ...
,
silicon
Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic ta ...
and
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
, and which may also contain water. These include synthetic
amorphous
In condensed matter physics and materials science, an amorphous solid (or non-crystalline solid, glassy solid) is a solid that lacks the long-range order that is characteristic of a crystal.
Etymology
The term comes from the Greek ''a'' ("wi ...
sodium aluminosilicate, a few naturally occurring minerals and synthetic
zeolite
Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ・y where is either a metal ion or H+. These p ...
s. Synthetic amorphous sodium aluminosilicate is widely used as a food additive,
E 554.
Amorphous sodium aluminosilicate
This substance is produced with a wide range of compositions and has many different applications. It is encountered as an additive E 554 in food where it acts as an
anticaking (free flow) agent. As it is manufactured with a range of compositions it is not strictly a chemical compound with a fixed
stoichiometry
Stoichiometry refers to the relationship between the quantities of reactants and products before, during, and following chemical reactions.
Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equal ...
. One supplier quotes a typical analysis for one of their products as 14SiO
2·Al
2O
3·Na
2O·3H
2O,(Na
2Al
2Si
14O
32·3H
2O).
The
US FDA
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food s ...
has as of April 1, 2012 approved ''sodium aluminosilicate (sodium silicoaluminate)'' for direct contact with consumable items under 21 CFR 182.2727. Sodium aluminosilicate is used as
molecular sieve
A molecular sieve is a material with pores (very small holes) of uniform size. These pore diameters are similar in size to small molecules, and thus large molecules cannot enter or be adsorbed, while smaller molecules can. As a mixture of molec ...
in medicinal containers to keep contents dry.
Sodium aluminosilicate may also be listed as:
* aluminium sodium salt
* sodium silicoaluminate
* aluminosilicic acid, sodium salt
* sodium aluminium silicate
* aluminum sodium silicate
* sodium silico aluminate
* sasil
Minerals sometimes called sodium aluminosilicate
Naturally occurring minerals that are sometimes given the chemical name, sodium aluminosilicate include
albite
Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. It represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula . It is a tectosilicate. ...
(NaAlSi
3O
8, an end-member of the
plagioclase series) and
jadeite
Jadeite is a pyroxene mineral with composition Na Al Si2 O6. It is hard (Mohs hardness of about 6.5 to 7.0), very tough, and dense, with a specific gravity of about 3.4. It is found in a wide range of colors, but is most often found in shades ...
(NaAlSi
2O
6).
Synthetic zeolites sometimes called sodium aluminosilicate
Synthetic zeolites have complex structures and examples (with structural formulae) are:
*Na
12Al
12Si
12O
48·27H
2O, zeolite A (Linde type A sodium form, NaA), used in laundry detergents
[Alan Dyer, (1994),''Encyclopedia of Inorganic Chemistry'', ed R. Bruce King, John Wiley & Sons, ]
*Na
16Al
16Si
32O
96·16H
2O, Analcime, IUPAC code ANA
*Na
12Al
12Si
12O
48·q H
2O, Losod
["Formation and Properties of Losod, a New Sodium Zeolite", Werner Sieber, Walter M. Meie ''Helvetica Chimica Acta'', Volume 57 Issue 6, pp. 1533–1549, 10.1002/hlca.19740570608]
*Na
384Al
384Si
384O
1536·518H
2O, Linde type N
References
{{reflist
Inorganic compounds
Sodium compounds
Aluminosilicates
Zeolites
Food additives
E-number additives