boric acid

Also found in: Dictionary, Thesaurus, Medical, Legal, Acronyms, Wikipedia.

boric acid,

any one of the three chemical compounds, orthoboric (or boracic) acid, metaboric acid, and tetraboric (or pyroboric) acid; the term often refers simply to orthoboric acid. The acids may be thought of as hydrates of boric oxide, B2O3. Orthoboric acid, H3BO3 or B2O3·3H2O, is colorless, weakly acidic, and forms triclinic crystals. It is fairly soluble in boiling water (about 27% by weight) but less so in cold water (about 6% by weight at room temperature). When orthoboric acid is heated above 170°C; it dehydrates, forming metaboric acid, HBO2 or B2O3·H2O. 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, H4B4O7 or B2O3·H2O. Tetraboric acid is either a vitreous solid or a white powder and is water soluble. When tetraboric or metaboric acid is dissolved it reverts largely to orthoboric acid. The major uses of the boric acids are in forming other boron compounds and in borate salts, e.g., boraxborax
or sodium tetraborate decahydrate
, chemical compound, Na2B4O7·10H2O; sp. gr. 1.73; slightly soluble in cold water; very soluble in hot water; insoluble in acids.
..... Click the link for more information.
. A dilute water solution of boric acid is commonly used as a mild antiseptic and eyewash. Boric acid is also used in leather manufacture, electroplating, and cosmetics. Boric acid can be crystallized from an acidified borax solution. It occurs as the mineral sassolite in the Tuscan region of Italy, where it is also recovered from hot springs and vapors. In the United States boric acid is recovered from brines from Searles Lake in California.

Boric Acid


(also orthoboric acid), H3BO3, a weak inorganic tribasic acid; colorless crystals in the form of flakes. Density, 1.48 g/cm3. Moderately soluble in cold water and more soluble in hot water, which is used to purify it (solubility per 100 g H2O: 2.66 g at 0° C; 39.7 g at 100° C). Boric acid is soluble in alcohol and other organic substances. When heated it loses water, turning first into metaboric acid, HBO2, and then into boric anhydride, B2O3. The salts of boric acid—borates—are derived mainly from various polyboric acids with the general formula nB2O3 · mH2O. When boric acid reacts with alcohols in the presence of concentrated H2SO4 (for bonding water), esters—for example, boric methyl ester—are formed:

3CH3OH + H3BO3 = B(OCH3)3 + 3H2O

When ignited, the esters of boric acid burn with a green flame, which is a qualitative reaction for boron. Boric acid is found in nature in hot springs as a dissolved form and as vapor. It evolves in the form of the mineral sassolite from hot springs and excrustations in volcanic craters. The industrial significance of natural boric acid is relatively small; it is usually obtained during the processing of borates.

Large quantities of boric acid are used to produce enamel wares. In laboratory practice boric acid is used in the preparation of buffer systems. In medicine it is used as an antiseptic. Aqueous solutions of boric acid serve as mouth and throat rinses and eyewashes. Ointments, pastes, and powders with boric acid and boric alcohol (boric acid dissolved in alcohol) are administered for some skin diseases (boric alcohol is also prescribed as ear drops). Boric acid is an ingredient in contraceptives.


boric acid

[¦bȯr·ik ′as·əd]
(inorganic chemistry)
H3BO3 An acid derived from boric oxide in the form of white, triclinic crystals, melting at 185°C, soluble in water. Also known as boracic acid; orthoboric acid.

boric acid

1. a white soluble weakly acid crystalline solid used in the manufacture of heat-resistant glass and porcelain enamels, as a fireproofing material, and as a mild antiseptic. Formula: H3BO3
2. any other acid containing boron
References in periodicals archive ?
The selectivity value of the reverse osmosis membrane according to borate and polyborate ions is significantly higher than for boric acid, since the dimensions of the latter are close to the dimensions of water molecules (Fig.
Although the exact mechanism of this synthetic method is not clear, however, it's seems that boric acid by its weak Bronsted as well as Lewis acidity characters can activate the epoxide ring for heterolysis by Ac2O.
Percent mortality of Aedes taeniorhynchus at 48 h after exposure to 1% boric acid sugar baits sprayed on black mangrove and yaupon holly cuttings in the laboratory.
Table 1 shows that, the sludge obtained is lowest in the effluents treated with phosphoric acid and formic acid and highest in case of boric acid.
For each organic substrate, five specimens were mounted with the same composition, as indicated above, varying in the presence or absence of a catalyst, forming three groups, as follows, Group A: substrate without a catalyst; Group B: substrate with 30ml of 5% w/v boric acid ([H.
The ministry said it can well supply the requested amount of boric acid, with the reserve at home currently estimated at 309 tons.
South Korea is able to meet a request to supply Japan with around 53 tons of boric acid to assist in regulating the nuclear reactor issues, the South Korean government has said.
Scientists discovered some contain rat poison, boric acid and lead paints - and many are made by people with no medical qualifications.
THOUSANDS of Irish people are turning to the internet to buy medication - costing the Exchequer EUR86million a year, More than a third are going online to get their pills despite up to 90% of products on the web being fake and some containing rat poison, boric acid and lead paint.
Fake medicines can contain harmful ingredients such as rat poison, boric acid and lead paint.
Sugar water or soda, with a generous dose of boric acid dissolved in it, attracts those with a sweet tooth.