He Silicic acid , Is a hydrated form of silicon oxide. It is the general name for the family of chemical compounds formed by a silicon, and a certain amount of molecules of hydrogen and oxygen.
The general formula for these acids is [SiO X (OH) 4-2x ] N , And the most common form in which is usually found is in the Orthosilicic acid H 4 SiO 4 .
Figure 1: Structure of silicic acid.
Silicic acid is part of the family of Miscellaneous Silicates. This means that the largest metal oxoanion is the silicate, and that no non-metallic atom is attached to it. There are some isolated cases in which they have a nonmetallic atom, but never more than one.
Physical properties of silicic acid
Silicic acid only exists in two states, amorphous and crystalline. The first is obtained by a precipitation process and the second is presented as rock crystal.
Silicic acid in its amorphous form (SiO 3 ) Is white, unflavored, insoluble in water and does not form with some molecules of itself some cohesive plastic mass as with aluminum.
In its crystalline state, it is not dissolved by any oxacids. When a very dilute solution of silica solution is treated with sulfuric acid , Nitric or hydrochloric acid, silicic acid is not precipitated. Instead, it appears to be dissolved in water as a hydrate.
When a solution of the acid or acid is added to a silicate solution, the hydrate is precipitated in a gelatinous form which when dried and subsequently heated with high energy becomes an insoluble substance.
Chemical reactions
Silicic acid is extremely weak and only loses its first proton when approaching pH 10. Only 3 reactions with this acid that are given under normal physiological conditions of life are known.
- The reaction with itself when the solubility is exceeded to form amorphous silica hydrate.
- Its reaction with aluminum hydroxide to form aluminum silicate hydroxide.
- Reaction with excess molybdate to form heteropolyacids like silicomolybdate.
Where is the silica?
After oxygen, silicon is the most common element of nature, this is in the form of crystals. When in aqueous medium it becomes non-ionizing, so the silicon salts in the ocean can acidify the silicon and create silicic acid.
The net inputs of silicic acid in the world ocean have been found in 6.1 ± 2.0 teramoles of silicon per year (1 teramol = 1012 moles). Almost 80% of this contribution comes from rivers with a global mean concentration of 150 micromolar (concentration in water).
In modern marine sediments, net yields of biogenic silicon (conversion of dissolved silicate into particulate skeletal material) is 7.1 ± 1.8 teramoles per year.
The gross production of biogenic silica in surface waters is 240 ± 40 teramoles of silicon per year, and the preservation ratio (accumulation of opales in sediments / gross production in surface waters) is 3 percent.
In the flora can be found in the plant Borago officinalis (Borage), which in its composition has up to 2.2% of silicic acid.
Ortosilicic acid is the most common form of silicic acid, which can be found in different places. The largest bioavailable sources of this acid are found in water, either in sea water or in other beverages such as beer.
To obtain it in the laboratory follows the same principle as in the ocean, can be obtained by the acidification of sodium silicate in an aqueous solution.
Uses in everyday life
Toothpaste
It is the abrasive gel used in the toothpaste, or in the clear part of the streaked toothpaste, because in combination with calcium carbonate, helps to safely remove the plaque with brushing.
It is registered as a safe compound in the United States Food & Drug Administration and has no known toxicity or carcinogenicity.
Desiccant
When dried in an oven, it loses water and becomes a desiccant (substance that attracts water from the air). Small packets of silica gel crystals can therefore be found in containers whose contents may be damaged by moisture such as vitamin bottles, electronics, shoes or leather products.
Other uses
It can be found in gift shops like magic stones, chemical garden or glass garden. Its dry form is mixed with salts of different metals.
When released into the water, sodium is replaced by metal and as the metal silicate is not soluble in water, a precipitate of the characteristic color of the metal is formed. The metal silicate also expands as a gel and grows as colorful stalagmites in the water.
Medical benefits of orthosilicic acid (OSA)
Ortosilicic acid is the best bioavailable medium of silicon for humans. This can be used to treat various health conditions such as Alzheimer disease , Arthritis, atherosclerosis, hypertension, heart disease, osteoporosis, stroke and hair
Bone health
In a study of 136 women with osteopenia in 2008, orthosilicic acid was given along with calcium and vitamin D Or placebo every day for a year. After the year, participants who received the acid improved bone formation.
Scientists say this is due to the ability of orthosilicic acid to stimulate the production of Collagen (A protein found in connective tissue) and in promoting the development of bone-forming cells.
Health in the hair
A small study published in 2007 suggests that this acid can help improve hair quality and health. In the study, 48 women with"fine hair"were divided into two groups and given a placebo or an orthosilicic supplement for nine months.
Researchers found that orthosalicylic acid appeared to increase hair strength and thickness. In general the quality of hair has also been improved with supplementation of orthosalicylic acid.
References
- National Center for Biotechnology Information. PubChem Compound Database; CID = 14942. Retrieved from: pubchem.ncbi.nlm.nih.gov.
- Graham, T. (1863). On the Properties of Silicic Acid and other Analogous Colloidal Substances. Proceedings of the Royal Society of London, 13, 335-341. Retrieved from: jstor.org.
- The Editors of Encyclopedia Britannica (1998) Silicic Acid Chemical Compound. Encyclopedia Britannica. Retrieved from: britannica.com.
- Tomsofmaine.com. (2017). Hydrated Silica | Tom's of Maine. [Online] Retrieved from: tomsofmaine.com.
- William Thomas Brande, Alfred Swaine Taylor. Chemistry. Blanchard and Lea. [Online] Retrieved on March 21, 2017 from books.google.co.ve.id.
- Field, S. (2017). Hydrated silica. [Online] Retrieved on March 22, 2017 from: sci-toys.com.
- Chemspider.com (2017). Orthosilicic acid (H4O4Si) ChemSpider. [Online] Retrieved on March 22, 2017 from: chemspider.com.
- Sanchez, B. (2017). Silicic acid: properties and health benefits. [Online] Organic silicon. Retrieved on March 22, 2017 from: elsilicioorganico.com.
- Treguer, P., Nelson, D., Van Bennekom, A., DeMaster, D., Leynaert, A. and Queguiner, B. (2017). The Silica Balance in the World Ocean: The Reestimate. [Online] Retrieved on March 23, 2017 from science.sciencemag.org.
- Jurkić, L., Cepanec, I., Kraljević Pavelić; Krešimir Pavelić, S., Pavelić, K. and Pavelić, K. (2013). Biological and Therapeutic Effects of Ortho-Silicic Acid. [Online] Medscape. Retrieved on March 21, 2017 from: medscape.com.
- Sahelian, M.D., R. (2016). Silicon supplement, orthosilicic acid. [Online] Raysahelian.com. Retrieved on March 25, 2017 from: raysahelian.com.