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Encyclopedia > Boric acid
Boric acid
Other names Orthoboric acid,
Boracic acid,
Sassolite,
Optibor®,
Borofax®
Identifiers
CAS number 10043-35-3
Properties
Molecular formula B(OH)3
Molar mass 61.832 g/mol
Appearance White crystalline solid
Density 1.435 g/cm³, solid.
Melting point

169°C decomp. Image File history File links A sample of boric acid. ... Image File history File links Size of this preview: 800 × 487 pixelsFull resolution (1100 × 669 pixel, file size: 106 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... For other uses, see Density (disambiguation). ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...

Solubility in water 5.7 g/100 ml (25°C)
Acidity (pKa) 9.24 (see text)
Structure
Molecular shape Planar
Dipole moment Zero
Hazards
MSDS External MSDS
NFPA 704

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 acid dissociation constant (Ka), also known as the acidity constant or the acid-ionization constant, is a specific equilibrium constant for the reaction of an acid with its conjugate base in aqueous solution [1]. // When an acid dissolves in water, it partly dissociates forming hydronium ions and its conjugate... four sp³ orbitals three sp² orbitals In chemistry, hybridisation or hybridization (see also spelling differences) is the concept of mixing atomic orbitals to form new hybrid orbitals suitable for the qualitative description of atomic bonding properties. ... The Earths magnetic field, which is approximately a dipole. ... An example MSDS in a US format provides guidance for handling a hazardous substance and information on its composition and properties. ... This page provides supplementary chemical data on boric acid. ... NFPA 704 is a standard maintained by the U.S. National Fire Protection Association. ... Image File history File links NFPA_704. ...

0
1
0
 
Flash point Non-flammable.
Related Compounds
Related compounds Boron trioxide
Borax
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Boric acid, also called boracic acid or orthoboric acid or Acidum Boricum, is a mild acid often used as an antiseptic, insecticide, flame retardant, in nuclear power plants to control the fission rate of uranium, and as a precursor of other chemical compounds. It exists in the form of colorless crystals or a white powder and dissolves in water. It has the chemical formula H3BO3, sometimes written B(OH)3. When occurring as a mineral, it is called sassolite. For other uses, see Flash point (disambiguation). ... Boron oxide is one of the oxides of boron. ... Borax from Persian burah. ... This page provides supplementary chemical data on boric acid. ... This page provides supplementary chemical data on boric acid. ... 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. ... This page provides supplementary chemical data on boric acid. ... This page provides supplementary chemical data on boric acid. ... 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 infrared region of the electromagnetic spectrum. ... Nuclear magnetic resonance spectroscopy most commonly known as NMR spectroscopy is the name given to the technique which exploits the magnetic properties of certain nuclei. ... Mass spectrometry (previously called mass spectroscopy (deprecated)[1] or informally, mass-spec and MS) is an analytical technique used to measure the mass-to-charge ratio of ions. ... The plimsoll symbol as used in shipping In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals exactly). ... For other uses, see Acid (disambiguation). ... An antiseptic solution of Povidone-iodine applied to an abrasion Antiseptics (Greek αντί, against, and σηπτικός, putrefactive) are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction. ... It has been suggested that ovicide be merged into this article or section. ... Socks made from flame retardant cotton. ... General Name, symbol, number uranium, U, 92 Chemical series actinides Group, period, block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Standard atomic weight 238. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number boron, B, 5 Chemical series metalloids Group, Period, Block 13, 2, p Appearance black/brown Standard atomic weight 10. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... For other uses, see Mineral (disambiguation). ... Sassolite is a borate mineral, and is the mineral form of boric acid. ...

Contents

Preparation

Boric acid is produced mainly from borate minerals by the reaction with sulfuric acid. The largest source of borates in the world is an open-pit mine in Boron, California, USA. Template:Chembox new Sulfuric (or sulphuric) acid, H2SO4, is a strong mineral acid. ... The El Chino mine located near Silver City, New Mexico is an open-pit copper mine Open-pit mining refers to a method of extracting rock or minerals from the earth by their removal from an open pit or borrow. ... Boron is a census-designated place located in Kern County, California. ...


Properties

Boric acid was first prepared by Wilhelm Homberg (1652-1715) from borax, by the action of mineral acids, and was given the name sal sedativum Hombergi ("sedative salt of Homberg"). The presence of boric acid or its salts has been noted in sea-water. It is also said to exist in plants and especially in almost all fruits (A. H. Allen, Analyst, 1904, 301). The free acid is found native in certain volcanic districts such as Tuscany, the Lipari Islands and Nevada, issuing mixed with steam from fissures in the ground; it is also found as a constituent of many minerals (borax, boracite, boronatrocaicite and colemanite).Boric acid is soluble in boiling water. When heated above 170°C it dehydrates, forming metaboric acid HBO2. Metaboric acid is a white, cubic crystalline solid and is only slightly soluble in water. It melts at about 236°C, and when heated above about 300°C further dehydrates, forming tetraboric acid or pyroboric acid, H2B4O7. Boric acid can refer to any of these compounds. Further heating leads to boron trioxide. Borax from Persian burah. ... Boron oxide is one of the oxides of boron. ...


Boric acid does not dissociate in aqueous solution, but is acidic due to its interaction with water molecules: H2O and HOH redirect here. ...

B(OH)3 + H2O ⇌ B(OH)4 + H+
Ka = 5.8x10−10 mol/l; pKa = 9.24.

Polyborate anions are formed at pH 7–10 if the boron concentration is higher than about 0.025 mol/L. The best known of these is the tetraborate ion, found in the mineral borax: The structure of the tetrahydroxyborate anion A ball-and-stick model of B(OH)4− Tetrahydroxyborate, [H4BO4]− or B(OH)4−, is a boron oxoanion with a tetrahedral geometry. ...

4B(OH)4 + 2H+ ⇌ B4O72− + 9H2O

Crystal structure

Crystalline boric acid consists of layers of B(OH)3 molecules held together by hydrogen bonds. The distance between two adjacent layers is 318 pm.

the unit cell of boric acid
hydrogen bonding (dashed lines)
allows boric acid molecules to form
parallel layers in the solid state

Image File history File links Size of this preview: 736 × 600 pixelsFull resolution (1100 × 896 pixel, file size: 252 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Size of this preview: 800 × 489 pixelsFull resolution (1000 × 611 pixel, file size: 279 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ... In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... An example of a quadruple hydrogen bond between a self-assembled dimer complex reported by Meijer and coworkers. ...

Toxicology

Boric acid is poisonous if taken internally or inhaled although it is generally not considered to be much more toxic than table salt (based on its mammal LD50 rating of 2660mg/kg body mass).[1][unreliable source?]. The Thirteenth Edition of the Merck Index indicates that the LD50 of boric acid is 5.14 g/kg for oral dosages given to rats, and that 5 to 20 g/kg has produced death in adult humans. The LD50 of sodium chloride is reported to be 3.75 g/kg in rats according to the Merk Index. According to the Dutch Health Council(1998/19) Boric Acid should be regarded as if it impairs fertility in humans(R60). Edible salt is a mineral, one of the few rocks people eat. ... An LD50 test being administered In toxicology, the LD50 or colloquially semilethal dose of a particular substance is a measure of how much constitutes a lethal dose. ...


However, boric acid is toxic to unborn infants. Also, it has been associated with low birth weight, eye malformations and problems with the nervous system.[citation needed]


Uses

Medicinal uses

It can be used as an antiseptic for minor burns or cuts and is sometimes used in dressings or salves or is applied in a very dilute solution as an eye wash. (1.5% solution or 1 tbsp per quart of boiled water has been suggested for the latter.) As an anti-bacterial compound, boric acid can also be used as an acne treatment. Boric acid can be used to treat yeast and fungal infections such as candidiasis (vaginal yeast infections) by inserting a vaginal suppository containing 600 mg of boric acid daily for 14 days (PMID 10865926). It is also used as prevention of athlete's foot, by inserting powder in the socks or stockings, and in solution can be used to treat some kinds of otitis externa (ear infection) in both humans and animals. The preservative in urine sample bottles (red cap) in the UK is boric acid. An antiseptic solution of Povidone-iodine applied to an abrasion Antiseptics (Greek αντί, against, and σηπτικός, putrefactive) are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction. ... An antiseptic is a substance that kills or prevents the growth and reproduction of various microorganisms, including bacteria, fungi, protozoa, and viruses on the external surfaces of the body. ... Typical divisions Ascomycota (sac fungi) Saccharomycotina (true yeasts) Taphrinomycotina Schizosaccharomycetes (fission yeasts) Basidiomycota (club fungi) Urediniomycetes Sporidiales Yeasts are a growth form of eukaryotic microorganisms classified in the kingdom Fungi, with approximately 1,500 species described. ... The Term mycosis (plural: mycoses) refers to conditions in which fungi pass the resistance barriers of the human or animal body and establish infections. ... Athletes foot or Tinea pedis[1] is a parasitic fungal infection of the epidermis of the foot. ... This article or section is in need of attention from an expert on the subject. ...


Boric acid has the distinction of being the only known acid that is actually beneficial (rather than harmful) to the eyes, and as such is used by ophthalmologists and in some commercial eye drops. This article is about the branch of medicine. ... Eye Drops was a television program on TechTV that showcased short computer animation movies and clips made using off the shelf 3D animation software. ...


Insecticidal use

Boric acid was first registered as an insecticide in 1948 by the EPA for control of cockroaches, termites, fire ants, fleas, silverfish, and many other insects. [2] It acts as a stomach poison affecting the insects' metabolism, and the dry powder is abrasive to the insects' exoskeleton. EPA redirects here. ... For other uses, see Cockroaches. ... Families Mastotermitidae Kalotermitidae Termopsidae Hodotermitidae Rhinotermitidae Serritermitidae Termitidae Wikispecies has information related to: Isoptera Termites, sometimes known as white ants, are a group of social insects usually classified at the taxonomic rank of order Isoptera. ... Species More than 280 species and subspecies, see text Fire ants, sometimes referred to as simply red ants, are stinging ants of which there are over 280 species worldwide. ... For other uses, see Flea (disambiguation). ... Binomial name Linnaeus, 1758 For other uses, see Silverfish (disambiguation). ... Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... An abrasive is a material, often a mineral, that is used to shape or finish (see metal polishing and wood finishing) a workpiece through rubbing which leads to part of the workpiece being worn away. ...


Boric acid may be used either in an insect bait formulation containing a feed attractant or as a dry powder. The powder may be injected into cracks and crevices, where it forms a fine layer of dust. Insects travel through the boric acid dust, which adheres to their legs. When the insects groom themselves, they then ingest the poison, which causes death three to ten days later of starvation and dehydration.


Preservative Use

In combination with its use as an insecticide it also prevents and destroys existing wet and dry rot in timbers. It can be used in combination with an ethylene glycol carrier to treat external wood against fungal and insect attack. It is possible to buy Borate impregnated rods for insertion into wood via drill holes where damp and moisture is known to collect and sit. It is available in a gel form and injectable paste form for treating rot affected wood without the need to replace the timber. You can buy concentrates of Borate based timber treatments which can be sprayed or dipped. Surface treatments prevent slime, mycelium and algae growth even in marine environments. There is a wide range of manufacturers of wood preservers based on boric acid/ borate mineral salts.


Industrial uses

Boric acid is used in nuclear power plants to slow down the rate at which fission is occurring. Fission chain reactions are generally driven by the amount of neutrons present (as products from previous fissions). Natural Boron is 20% Boron-10 and about 80% Boron-11. Boron-10 has a high cross-section for absorption of low energy (thermal) neutrons. By adding more boric acid to the reactor coolant which circulates through the reactor, the probability that a neutron can survive to cause fission is reduced. Therefore, boric acid concentration changes effectively regulate the rate of fissions taking place in the reactor. This is only done in Pressurized Water Reactors (PWR's). Boron is also dissolved into the spent fuel pools containing used uranium rods. The concentration is high enough to keep fissions at a minimum.


In the jewelry industry, boric acid is often used in combination with denatured alcohol to reduce surface oxidation and firescale from forming on metals during annealing and soldering operations. Denatured alcohol is ethanol with added adulterants that make it useless for consumption as an intoxicating beverage by rendering it toxic or extremely distasteful to drink, but still useful for industrial processes or as a household chemical. ... The most fundamental reactions in chemistry are the redox processes. ... For other uses, see Annealing. ... (De)soldering a contact from a wire. ...


It is also used in the manufacturing of remming mass, a fine silica-containing powder used for producing induction furnace linings and ceramics. The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... An induction furnace, with fume hood closed, tapping a melt An induction furnace is an electrical furnace in which the heat is applied by induction heating of a conductive medium (usually a metal) in a crucible around which water-cooled magnetic coils are wound. ... Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεραμικός (keramikos). ...


Miscellaneous uses

Borates including boric acid have been used since the time of the Greeks for cleaning, preserving food, and other activities. Borates in chemistry are chemical compounds containing boron bonded to three oxygen atoms written as B(OR)3. ...


Silly Putty was originally made by adding boric acid to silicone oil. Now name-brand Silly Putty also contains significant amounts of elemental silicon (silicon binds to the silicone and allows the material to bounce 20% higher). Silly putty dripping through a hole Silly Putty shown as a solid cube Silly Putty (originally called nutty putty, and also known as Potty Putty) is a silicone plastic, marketed today as a toy for children, but originally created as a fortuitous accident during the course of research into potential... Silicone oils (polymerized siloxanes) are silicon analogues of carbon based organic compounds, and can form (relatively) long and complex molecules based on silicon rather than carbon. ... Not to be confused with Silicone. ...


Lithium borate is the lithium salt of boric acid and is used in the laboratory as buffer for gel. TBE buffer is widely used for the electrophoresis of nucleic acids and has a higher buffer capacity than a TAE Buffer. It can be used for DNA and RNA polyacrylamide and agarose gel electrophoresis. Lithium boric acid is the lithium salt of boric acid. ... TBE buffer is widely used for the electrophoresis of nucleic acids and has a higher buffer capacity than TAE. It can be used for DNA and RNA polyacrylamide and agarose gel electrophoresis. ... For specific types of electrophoresis (for example, the process of administering medicine, iontophoresis), see electrophoresis (disambiguation). ... Look up nucleic acid in Wiktionary, the free dictionary. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Left: An RNA strand, with its nitrogenous bases. ... Polyacrylamide is an acrylate polymer formed from acrylamide subunits that is readily cross-linked. ... Digital image of 3 plasmid restriction digests run on a 1% w/v agarose gel, 3 Volts/cm, stained with ethidium bromide. ...


It is used in pyrotechnics to prevent the amide-forming reaction between aluminum and nitrates. A small amount of boric acid is added to the composition to neutralize alkaline amides that can react with the aluminum. Pyrotechnics is a field of study often thought synonymous with the manufacture of fireworks, but more accurately it has a wider scope that includes items for military and industrial uses. ... Amide functional group Amides possess a conjugated system spread over the O, C and N atoms, consisting of molecular orbitals occupied by delocalized electrons. ... Aluminum is a soft and lightweight metal with a dull silvery appearance, due to a thin layer of oxidation that forms quickly when it is exposed to air. ...


Boric acid is popularly used among fire jugglers and fire spinners dissolved in methanol to give a deep green flame. Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a distinctive odor that is somewhat milder and sweeter than ethanol (ethyl alcohol). ...


It is also used in India and across the world to dust down Carrom boards to decrease friction and increase speed of play. For the games with billiard balls, see Carom billiards, or Cue sport more generally. ...


Boric acid is also used in special effects. When Boric Acid is combined with an alcohol (usually ethanol), it produces a green flame when burned.


References

  • Jolly, W. L. (1991). Modern Inorganic Chemistry (2nd Edn.). New York: McGraw-Hill. ISBN 0-07-112651-1. 

Further reading

External links

  • Louis Goodman, Alfred Gilman, Laurence Brunton, John Lazo and Keith Parker (2006). Goodman & Gilman's The Pharmacological Basis of Therapeutics. New York: McGraw Hill. 

  Results from FactBites:
 
What is Boric Acid (1187 words)
Pharmaceuticals: boric acid is a mild antiseptic as well as a mild acid that inhibits the growth of microorganisms on the external surfaces of the body.
Boric acid also aids in the fiberization process of fiberglass, which is used in fiberglass insulation as well as in textile fiberglass (which is a fabric-like material commonly used in skis, circuit boards, and other similar applications).
Boric acid and related compounds are being used as a source of hydrogen in the development of fuel cells and other “clean” fuel technologies.
Boric Acid - LoveToKnow 1911 (988 words)
The free acid is found native in certain volcanic districts such as Tuscany, the Lipari Islands and Nevada, issuing mixed with steam from fissures in the ground; it is also found as a constituent of many minerals (borax, boracite, boronatrocalcite and colemanite).
Boric acid is also obtained from boronatrocalcite by treatment with sulphuric acid, followed by the evaporation of the solution so obtained.
That orthoboric acid is a tribasic acid is shown by the formation of ethyl orthoborate on esterification, the vapour density of which corresponds to the molecular formula B(0C2H5)3; the molecular formula of the acid must consequently be B(OH) 3 or H 3 B0 3.
  More results at FactBites »

 
 

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