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Sodium Metaborate is used composition of herbicides.
Sodium Metaborate is used raising the pH of injected fluids for oil extraction.
Sodium Metaborate is used essential buffering agent.
CAS Number (anhydrous): 7775-19-1
Other CAS (tetrahydrate): 10555-76-7
EC (EINECS) Number: 231-891-6
Molecular Formula: NaBO₂ (anhydrous)
Molecular Weight: ~65.8 g/mol (anhydrous)
SYNONYMS:
NaBO₂, sodium borate, boric acid (HBO₂), sodium salt, boric acid monosodium salt, monosodium metaborate, sodium dioxoborate, Rasorite, Kodalk, sodium metaborate anhydrous, sodium metaborate tetrahydrate, sodium metaborate 4H₂O, sodium metaborate octahydrate, disodium dioxoborate, sodiummetaboratetetrahydrate,SODIUM METABORATE,Borosoap,7775-19-1,Kodalk,Boric acid (HBO2), sodium salt,Sodium borate (NaBO2),Sodium metaborate, anhydrous,Boric acid, monosodium salt,Monosodium metaborate,Z6Q395A23R,Boric acid (HBO2), sodium salt (1:1), DTXSID2034386, CHEBI:75227, RefChem:887672,DTXCID0014386,231-891-6,sodium,oxido(oxo)borane,SODIUMMETABORATE,Sodium(1+), (metaborato-O)-,Caswell No. 779AA,HSDB 5045,EINECS 231-891-6,EPA Pesticide Chemical Code 011104,UNII-Z6Q395A23R,NaBO2,EC 231-891-6,SCHEMBL24708,98536-58-4,SODIUM METABORATE [MI],SODIUM METABORATE [HSDB],SODIUM BORATE (NA2(BO2)2),AKOS024426998,NS00093515,Q3333421,Boric acid (HBO2), sodium salt, Borosoap, Kodalk, Sodium borate, Sodium borate (NaBO2), Boric acid, monosodium salt, Sodium metaborate, anhydrous,disodium borate, heptahydrate,disodium borate, monohydrate, Komex,monosodium metaborate,sodium borate,sodium borate (NaBO2),sodium diborate,sodium meta borate,sodium metaborate,sodium tetraborate
Sodium metaborate is a colorless solid chemical compound of sodium, boron, and oxygen with formula NaBO2.
Sodium Metaborate is used as a mild alkali accelerator in developers with moderate to high alkalinity, and also helps to avoid the creation of gas when it comes in contact with an acid.
Borates are also being developed as an alkaline agent in several enhanced oil recover (EOR) processes, such as alkali-polymer and alkali-surfactant-polymer (ASP) flooding.
Tertiary oil recovery from borate-based ASP core floods is comparable to that obtained with similar formulations that contain conventional alkalis and exhibit no injectivity problems in core flood trials.
Sodium Metaborate is a white solid; Hydrate: Cream colored powder; Commercially available as octahydrate and tetrahydrate;
Sodium Metaborate is an alkaline salt with excellent buffering properties.
Sodium Metaborate can also be used in the production of adhesives due to the high degree of alkalinity and the crosslinking reaction of borate anions with polyhydroxy groups.
Sodium metaborate is a chemical compound of sodium, boron, and oxygen with formula NaBO2.
However, Sodium Metaborate ion is trimeric in the anhydrous solid, therefore a more correct formula is Na3B3O6 or (Na+)3[B3O6]3−.
The formula of Sodium Metaborate can be written also as Na2O·B2O3 to highlight the relation to the main oxides of sodium and boron.
The name of Sodium Metaborate is also applied to several hydrates whose formulas can be written NaBO2·nH2O for various values of n.
The anhydrous and hydrates are colorless crystalline solids.
The anhydrous form is hygroscopic.
Sodium metaborate is an inorganic boron-containing compound consisting of sodium (Na), boron (B) and oxygen (O).
Sodium Metaborate is primarily encountered as the sodium salt of metaboric acid, commonly written with empirical formula NaBO₂, but structurally the metaborate anion exists as cyclic or oligomeric borate clusters in the solid.
Multiple hydrates (tetrahydrate, dihydrate) are known and commercially significant, but the anhydrous form (NaBO₂) is typically the reference for the “metaborate” term.
USES and APPLICATIONS of SODIUM METABORATE:
Sodium Metaborate is used in cleansers, detergents, adhesives, and photographic solutions.
Sodium Metaborate is also used as a fire retardant in sodium chlorate, a defoliant; a textile finishing agent, and a sequestrant.
Tetrahydrate: Sodium Metaborate is used as an insecticide, fungicide, nematocide, and herbicide (non-crop land, cotton production, and under asphalt).
Sodium Metaborate workers in mining and processing are exposed.
Sodium metaborate has diverse industrial applications.
Sodium Metaborate is a raw material in glass and ceramics production, particularly in borosilicate glass formulations that require boron to lower thermal expansion and improve thermal shock resistance.
Sodium Metaborate is used in textile finishing, detergent and cleaning product components, and adhesives and may serve as a sequestrant or buffer in various formulations.
The tetrahydrate form of Sodium Metaborate is sometimes used as a boron fertilizer in agriculture to supply micronutrient boron essential for plant growth, particularly in crops like maize.
In chemical synthesis, sodium metaborate can be a precursor for producing sodium borohydride, a reducing agent and hydrogen storage medium under research.
Sodium Metaborate has also been proposed as an ingredient in herbicide compositions, antifreeze fluids, and metallurgical fluxes.
Current and proposed applications of sodium metaborate include:
Manufacture of borosilicate glasses, which are resistant to uneven or fast heating because of their small coefficient of thermal expansion.
Sodium Metaborate is used composition of herbicides.
Sodium Metaborate is used raising the pH of injected fluids for oil extraction.
Sodium Metaborate is used essential buffering agent
Sodium Metaborate is used in the preparation of starch and dextrin adhesives, this product provides increased viscosity, quicker tack, and better fluidity.
In textile processing, sodium metaborate helps to stabilize hydrogen peroxide solutions and neutralizes acidic oxidation by-products.
High solubility for higher concentrations: Sodium Metaborate, available in 4 mol or 8 mol, is an alkaline salt with excellent buffering capacity.
As a result, Sodium Metaborate is an excellent choice for use in starch and dextrin adhesives (among other applications).
Starch-based adhesives have been a vital component of corrugated paper and paperboard.
Sodium metaborate’s high alkalinity helps it break the hydrogen bonding between starch chains—and producing even more extensive chemical changes that create a more highly branched chain polymer of higher molecular weight.
The result?
Adhesives with increased viscosity, quicker tack, and better fluid properties than those that don’t use borates.
These properties make the adhesive easier to work with.
For example, quick tack at reasonably low temperatures is necessary for the proper maintenance of corrugated paperboard machines, which operate at a high speed.
BENEFITS AND CHARACTERISTICS of SODIUM METABORATE:
The main technical benefits of sodium metaborate lie in its chemical stability at high temperatures, useful boron content, water solubility, and utility as a chemical intermediate.
Its function as a boron source makes Sodium Metaborate valuable in materials science (glasses, ceramics), industrial chemistry (synthesis intermediates), and agriculture (micronutrient supplementation).
Sodium Metaborate's alkaline solutions can buffer and adjust pH in process streams.
Sodium Metaborate's hydrated forms are easier to handle in lower-temperature applications, while the anhydrous form is suitable for high-temperature processing.
Sodium metaborate is an inorganic sodium salt having metaborate as the counterion.
Sodium Metaborate is an inorganic sodium salt and a member of borate salts.
FUNCTIONAL CHARACTERISTICS of SODIUM METABORATE:
Sodium metaborate is a source of borate ions, which confer characteristic buffering and alkalinity in aqueous solutions.
Sodium Metaborate moiety can interact with diols and polyols via reversible complexation, a feature utilized in some industrial processes.
Because of its heat stability, Sodium Metaborate is useful in high-temperature manufacturing contexts.
PHYSICAL AND CHEMICAL PROPERTIES of SODIUM METABORATE:
In its anhydrous form, sodium metaborate is a colorless to white crystalline solid that is odorless and generally appears as small prisms or crystals.
Sodium Metaborate has a high melting point (~966 °C) and a very high boiling point (~1434 °C, at which it decomposes rather than volatilizes).
The density of the anhydrous solid is approximately 2.46 g/cm³.
Sodium Metaborate is soluble in water, with solubility increasing with temperature, dissolving to tens of grams per 100 mL of water across typical ranges; it is insoluble or very slightly soluble in alcohols or ethers.
Sodium Metaborate exists with a trigonal crystal system in the solid state for the anhydrous form.
Sodium metaborate also forms hydrated crystalline forms, including the tetrahydrate (NaBO₂·4H₂O) and dihydrate (NaBO₂·2H₂O).
The tetrahydrate has a much lower melting/dehydration range (around ~54–57 °C) and is hygroscopic, meaning it readily absorbs water from the atmosphere.
Aqueous solutions of the tetrahydrate exhibit alkaline pH (approximately 10.5–12 at 10 g/L, 25 °C).
STRUCTURE AND CHEMISTRY of SODIUM METABORATE:
Unlike many simple salts, Sodium Metaborate ion in the solid can be oligomeric (e.g., trimeric rings) rather than simple monomeric BO₂⁻ units.
These rings involve alternating B and O atoms with bridging oxygens in a six-membered ring, typical in solid alkali metaborates.
In solution, the species can exist in various equilibrium forms depending on pH and concentration.
HYDRATES AND SOLUBILITY of SODIUM METABORATE:
The following hydrates crystallize from solutions of the proper composition in various temperature ranges:
tetrahydrate NaBO2·4H2O from −6 to 53.6 °C
dihydrate NaBO2·2H2O from 53.6 °C to 105 °C
hemihydrate NaBO2·0.5H2O from 105 °C to the boiling point.
Early reports of a monohydrate NaBO2·H2O have not been confirmed.
STRUCTURE of SODIUM METABORATE:
ANHYDROUS
Solid anhydrous sodium metaborate has the hexagonal crystal system with space group R3¯c.
Sodium Metaborate actually contains a six-membered rings with the formula [B3O6]3−, consisting of alternating boron and oxygen atoms with one negatively charged extra oxygen atom attached to each boron atom.
All nine atoms lie on a plane.
The six oxygen atoms are evenly divided into two distinct structural sites, with different B–O bond lengths: B–O(external) 128.0 pm and B–O(bridge) 143.3 pm.
The density is 2.348 ± 0.005 g/cm3.
The approximate dimensions of the hexagonal cell are a = 1275 pm, c = 733 pm.
However, the true unit cell is rhombohedral and has dimensions: ar= 776 pm, α = 110.6°, Z = 6 (5.98) molecules KB0.
DIHYDRATE
The dihydrate NaBO2·2H2O crystallizes in the triclinic crystal system, but is nearly monoclinic, with both α and γ very close to 90°.
The cell parameters are a = 678 pm , b = 1058A pm, c = 588 pm, α = 91.5°, β = 22.5°, γ = 89°, Z = 4, density 1.905 g/cm3.
The refractive indices at 25°C and wavelength 589.3 nm are α = 1.439, β = 1.473, γ = 1.484.
The dispersion is strong, greater at red than at violet.
The transition temperature between the dihydrate and the hemihydrate is 54 °C.
However, the crystalline dihydrate will remain metastable until 106 °C to 110 °C, and change slowly above that temperature.
VAPOR
Infrared spectroscopy of the vapor from anhydrous sodium metaborate, heated to between 900 °C and 1400 °C, shows mostly isolated clusters with formula NaBO2, and some dimers thereof.
Electron diffraction studies by Akishin and Spiridonov showed a structure O=B−O−Na with linear anion O=B−O− and angle B−O−Na of 90-110°.
The atomic distances are O=B: 120 pm, B−O: 136 pm, O−Na: 214 pm.
PREPARATION of SODIUM METABORATE:
Sodium metaborate is prepared by the fusion of sodium carbonate and boron oxide B2O3 or borax Na2B4O7.
Another way to create the compound is by the fusion of borax with sodium hydroxide at 700 °C:
B2O3 + 2 NaOH → 2 NaBO2 + H2O
The boiling point of sodium metaborate (1434 °C) is lower than that of boron oxide (1860 °C) and borax (1575 °C).
In fact, while the metaborate boils without change of composition, borax gives off a vapor of sodium metaborate with a small excess of sodium oxide Na2O.
The anhydrous salt can also be prepared from the tetraborate by heating to 270 °C in vacuum.
Although not performed industrially, hydrolysis of sodium borohydride Na[BH4] with a suitable catalyst gives sodium metaborate and hydrogen gas:
Na[BH4] + 2 H2O → NaBO2 + 4 H2 (ΔH = −217 kJ/mol)
REACTIONS of SODIUM METABORATE:
WITH WATER
When sodium metaborate is dissolved in water, the anion combines with two water molecules to form the tetrahydroxyborate anion [B(OH)4]−.
ELECTROCHEMICAL CONVERSION TO BORAX
Electrolysis of a concentrated aqueous solution of 20% NaBO2·4H2O with an anion exchange membrane and inert anode (such as gold, palladium, or boron-doped diamond) converts the metaborate anion to tetraborate B4O2−7, and the sodium salt of the latter (borax) precipitates as a white powder.
8BO2− → 2B4O2−7 + O2 + 4 e−
REDUCTION TO SODIUM BOROHYDRIDE
Sodium metaborate can be converted to sodium borohydride by several methods, including the reaction with various reducing agents at high temperatures and pressure, or with magnesium hydride MgH2 by ball milling at room temperature, followed by extraction of the Na[BH4] with isopropylamine.
NaBO2 + 2 MgH2 → Na[BH4] + 2 MgO
Another method is the electrolytic reduction of a concentrated sodium metaborate solution, namely
BO2− + 6 H2O + 8 e− → [BH4]− + 8 OH−
However, this method is not efficient since it competes with the reduction of hydroxide:
4 OH− → 2 H2O + O2 + 4 e−
Nanofiltration membranes can effectively separate the borohydride from the metaborate.
REACTION WITH ALCOHOLS
Anhydrous sodium metaborate refluxed with methanol yields the corresponding sodium tetramethoxyborate (melting point: 253-258 °C, CAS number: 18024-69-6):
Na+BO2− + 4 CH3OH → Na+[B(OCH3)4]− + 2 H2O
The analogous reaction with ethanol yields the sodium tetraethoxyborate.
PHYSICAL and CHEMICAL PROPERTIES of SODIUM METABORATE:
CAS Number (anhydrous):7775-19-1
Other CAS (tetrahydrate):10555-76-7
EC (EINECS) Number:231-891-6
Molecular Formula:NaBO₂ (anhydrous)
Molecular Weight:~65.8 g/mol (anhydrous)
PubChem/Database ID:PubChem entry exists (identifier details on ECHA-listed substance).
Chemical formula:NaBO2
Molar mass:65.80 g·mol−1
Appearance:Colorless crystals
Odor:Odorless
Density:2.464 g/cm3 (anhydrous)
Melting point:966 °C (1,771 °F; 1,239 K)
Boiling point:1,434 °C (2,613 °F; 1,707 K)
Solubility in water:16.4 g/(100 mL) (0 °C)
28.2 g/(100 mL) (25 °C)
125.2 g/(100 mL) (100 °C)
Solubility:insoluble in ether, ethanol
Structure
Crystal structure:trigonal
Thermochemistry
Heat capacity (C):65.94 J/(mol·K)
Std molar entropy (S⦵298):73.39 J/(mol·K)
Std enthalpy of formation (ΔfH⦵298):−1059 kJ/mol
Molecular Weight:65.80 g/mol
Hydrogen Bond Donor Count:0
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:0
Exact Mass:65.9889037 Da
Monoisotopic Mass:65.9889037 Da
Topological Polar Surface Area:40.1 Ų
Heavy Atom Count:4
Formal Charge:0
Complexity:13.5
Isotope Atom Count:0
Defined Atom Stereocenter Count:0
Undefined Atom Stereocenter Count:0
Defined Bond Stereocenter Count:0
Undefined Bond Stereocenter Count:0
Covalently-Bonded Unit Count:2
Compound Is Canonicalized:Yes
Melting point:966 °C
Boiling point:1434 °C
Density:2.464
solubility:soluble in H2O
pka:8.94
form:white hexagonal crystals
color:white hexagonal, hexane crystals, crystalline
Water Solubility:g/100g solution H2O: 14.10 (0°C), 22.00 (25°C), 55.60 (100°C); solid phase, NaBO2 ·4H2O (0°C, 25°C), NaBO2 · 2H2O (100°C)
NIST Chemistry Reference:Sodium metaborate(7775-19-1)
EPA Substance Registry System:Sodium metaborate (7775-19-1)
FIRST AID MEASURES of SODIUM METABORATE:
-Description of first-aid measures
*General advice:
Show this material safety data sheet to the doctor in attendance.
*If inhaled:
After inhalation:
Fresh air.
*In case of skin contact:
Take off immediately all contaminated clothing.
Rinse skin with
water/ shower.
*In case of eye contact:
After eye contact:
Rinse out with plenty of water.
Call in ophthalmologist.
Remove contact lenses.
*If swallowed:
After swallowing:
Immediately make victim drink water (two glasses at most).
Consult a physician.
-Indication of any immediate medical attention and special treatment needed.
No data available
ACCIDENTAL RELEASE MEASURES of SODIUM METABORATE:
-Environmental precautions:
Do not let product enter drains.
-Methods and materials for containment and cleaning up:
Cover drains.
Collect, bind, and pump off spills.
Observe possible material restrictions.
Take up dry.
Dispose of properly.
Clean up affected area.
FIRE FIGHTING MEASURES of SODIUM METABORATE:
-Extinguishing media:
*Suitable extinguishing media:
Carbon dioxide (CO2)
Foam
Dry powder
*Unsuitable extinguishing media:
For this substance/mixture no limitations of extinguishing agents are given.
-Further information:
Prevent fire extinguishing water from contaminating surface water or the ground water system.
EXPOSURE CONTROLS/PERSONAL PROTECTION of SODIUM METABORATE:
-Control parameters:
--Ingredients with workplace control parameters:
-Exposure controls:
--Personal protective equipment:
*Eye/face protection:
Use equipment for eye protection.
Safety glasses
*Body Protection:
protective clothing
*Respiratory protection:
Recommended Filter type: Filter A
-Control of environmental exposure:
Do not let product enter drains.
HANDLING and STORAGE of SODIUM METABORATE:
-Conditions for safe storage, including any incompatibilities:
*Storage conditions:
Tightly closed.
Dry.
STABILITY and REACTIVITY of SODIUM METABORATE:
-Chemical stability:
The product is chemically stable under standard ambient conditions (room temperature).
-Possibility of hazardous reactions:
No data available
