Disodium octaborate
Repeating asymmetrical unit in α-Na2B8O13
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Names | |
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IUPAC name
Disodium;(9,11-dioxido-5-oxoboranyloxy-2,4,6,8,10,12,13-heptaoxa-1,3,5,7,9,11-hexaborabicyclo[5.5.1]tridecan-3-yl)oxy-oxoborane
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Other names
Sodium octaborate
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Identifiers | |
3D model (
JSmol ) |
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ECHA InfoCard
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100.114.740 |
EC Number |
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PubChem CID
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CompTox Dashboard (EPA)
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Properties | |
Na2B8O13 | |
Molar mass | 340.45 g·mol−1 |
Appearance | Colorless crystals |
9.5 g/(100 g)[2] | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Names | |
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Other names
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Identifiers | |
3D model (
JSmol ) |
|
ECHA InfoCard
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100.114.740 |
EC Number |
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PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
Na2B8O13·4H2O | |
Molar mass | 412.5270 g/mol |
Appearance | white powder |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Disodium octaborate is a
Disodium octaborate is traded either as a liquid concentrate, or as the
Preparation
The anhydrous form can be crystallized from a molten mixture of
Properties
Solubility
The salt dissolves in water to form forms viscous supersaturated solutions at elevated temperatures. Solubility of the tetrahydrate is 21.9% (wt) at 30 °C (303 K).[9]
Structure
The anhydrous salt exists in two stable crystalline forms, α and β.[10][11]
The α form has
The β form has monoclinic crystal structure, with the P21/c space group. The unit cell parameters are a = 1173.1 pm, b = 788.0 pm, c = 1041.0 pm, β = 99.883 °, Z = 4. The structure consists of two infinite, independent, and interleaved boron–oxygen networks containing a complex borate anion [B8O13]2− formed by six BO3 triangles (Δ) and two BO4 tetrahedra (T), which can be viewed as a B5O10 group linked to a B3O7 group. This fundamental building block is identical to that of the α form and of silver octaborate Ag2B8O13, with some subtle differences.[11]
Uses
Dilute solutions of disodium octaborate are sprayed on wood surfaces to kill
The compound was also shown to significantly reduce
Disodium octaborate, applied to the soil or foliar spray, has been shown to inhibit pests of crops such as tomato and pistachio, with no observed detrimental effects to the plants.[13][14]
Safety
Disodium octaborate is neither flammable, nor combustible or explosive and has low acute oral and dermal toxicity.[3] The oral 50% lethal doses (LD50) are 5.3 g/kg for guinea pig, 2g/kg for rats.[4] However, it is classified as "reproductive toxicity category 1B (presumed human reproductive toxicant)" under the EU Classification, Labelling and Packaging Regulation (CLP Regulation). The CLP hazard code and statement are "H360FD: May damage fertility. May damage the unborn child."
On 22 February 2018, the Swedish Chemicals Agency (KEMI) submitted a proposal to the European Chemicals Agency (ECHA) to list disodium borate as a Substance of Very High Concern (SVHC) under the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) Regulation.[15]
References
- ^ a b "Boron sodium oxide (B8Na2O13)". Substance page at the PubChem website. Accessed on 2022-06-28.
- ^ H. W. Scherer et al (2008): "Fertilizers". Chapter of Ullmann's Encyclopedia of Industrial Chemistry, 7th ed.
- ^ S2CID 59039873.
- ^ a b c "Disodium octaborate". Substance page at the National Institutes of Health - National Library of Medicine ChemDplus website. Accessed on 2022-06-28.
- ISBN 0-471-93620-0
- ^ a b "Polybor". Product data page at the U. S. Borax company website. Accessed on 2022-06-27.
- ^ "[1][permanent dead link]". Product data page at the U. S. Borax company website. Accessed on 2022-06-27.
- ^ C. J. Leedecke and C. G. Bergeron (1977): "Crystallisation of Na2B8O13 in Selected Na2O-B2O3 Melts". Physics and Chemistry of Glasses (UK), volume 18, issue 6, pages 116-120.
- ^ M. Briggs (2001): "Boron Oxides, Boric Acid, and Borates". Chapter of the Kirk-Othmer Encyclopedia of Chemical Technology. Wiley.
- ^ S2CID 95388918.
- ^ .
- S2CID 21252903.
- ^ H. Kavak, A. L. Tuna, and H. S. Civelek (2017): "Effects of Tarımbor (Na2B8O13.4(H2O)) fertiliser against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and biochemistry and physiology of tomato plants under greenhouse conditions." Ege Üniversitesi Ziraat Fakültesi Dergisi, volume 54, issue 2, pages 157-165 (in Turkish).
- .
- ^ "Proposal for Identification of a Substance of Very High Concern on the Basis of the Criteria Set Out in REACH Article 57", Swedish Chemicals Agency, 22 February 2018.