Disodium octaborate: Difference between revisions

| Verifiedfields =

| Watchedfields =

| verifiedrevid =

| ImageFile = Disodium octaborate.svg

| ImageCaption = Repeating asymmetrical unit in α-Na₂B₈O₁₃

| ImageSize = 120px

| Name = Disodium octaborate

| IUPACName = 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

| OtherNames = Sodium octaborate

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|??|chemspider}}

| ChemSpiderID =

| ChEMBL_Ref = {{ebicite|??|EBI}}

| ChEMBL =

| UNII_Ref = {{fdacite|??|FDA}}

| UNII =

| InChI = 1S/B8O13.2Na/c9-1-13-5-18-6(14-2-10)20-8-17-4(12)15-3(11)16-7(19-5)21-8;;/q-2;2*+1

| InChIKey = CGCGPGRQKOPVHP-UHFFFAOYSA-N

| SMILES = B(=O)OB1OB2OB(OB(OB(O2)OB(O1)OB=O)[O-])[O-].[Na+].[Na+]

| StdInChI_Ref = {{stdinchicite|??|chemspider}}

| StdInChI =

| StdInChIKey_Ref = {{stdinchicite|??|chemspider}}

| StdInChIKey =

| CASNo = 12008-41-2

| CASNo_Ref = <ref name=PubChem/>

| PubChem = 90479350

| EINECS = 234-541-0

| RTECS =

| UNNumber =

}}

|Section2={{Chembox Properties

| Formula = {{chem2|Na2B8O13}}

| Na=2|B=8|O=13

| Appearance = Colorless crystals

| Density =

| MeltingPtC =

| MeltingPt_notes =

| BoilingPtC =

| BoilingPt_notes =

| Solubility = 9.5 g/(100 g)<ref name=scher2008/>

| SolubleOther =

| Solubility1 =

| Solvent1 =

| Solubility2 =

| Solvent2 =

| Solubility3 =

| Solvent3 =

| RefractIndex =

| SolubilityProduct =

}}

|Section3={{Chembox Structure

| Coordination =

| CrystalStruct =

}}

|Section4={{Chembox Thermochemistry

| DeltaHf =

| HeatCapacity =

| DeltaGf =

| Entropy =

}}

}}

{{chembox

| verifiedrevid = 432633874

| Name = Disodium octaborate tetrahydrate

| OtherNames = {{ubl|Aquabor|Boron sodium oxide|Polybor|Sodium octaborate|Tim-bor insecticide}}

| CASNo_Ref = {{cascite|correct|??}}

| CASNo = 12280-03-4

| DTXSID = DTXSID1034391

| EINECS = 602-894-3

| PubChem = 90478478

| SMILES = B(=O)OB1OB2OB(OB(OB(O2)OB(O1)OB=O)[O-])[O-].O.O.O.O.[Na+].[Na+]

| InChI = InChI=1S/B8O13.2Na.4H2O/c9-1-13-5-18-6(14-2-10)20-8-17-4(12)15-3(11)16-7(19-5)21-8;;;;;;/h;;;4*1H2/q-2;2*+1;;;;

| InChIKey = RDMZIKMKSGCBKK-UHFFFAOYSA-N

| UNII = U2EEC8170G

| Formula = {{chem2|Na2B8O13*4H2O}}

| MolarMass = 412.5270 g/mol

| Appearance = white powder

| Density =

| Solvent = other solvents

| SolubleOther =

| MeltingPt =

'''Disodium octaborate''' is a [[borate]] of [[sodium]], a [[chemical compound]] of sodium, [[boron]], and [[oxygen]] — a [[salt (chemistry)|salt]] with [[elemental formula]] {{chem2|Na2B8O13}} or {{chem2|(Na+)2[B8O13](2-)}}, also written as {{chem2|Na2O*4B2O3}}. It is a colorless crystalline solid, soluble in water.

Disodium octaborate is traded either as a liquid concentrate, or as the [[hydrate|tetrahydrate]] {{chem2|Na2B8O13*4H2O}}, a white odorless powder. It is used as an [[insecticide]],<ref name=nany1998/><ref name=NIH/> and as a [[fungicide]] and [[algicide]], and as a [[fire retardant]].,<ref name=brot1994/><ref name=Polybor/> and as a boron [[micronutrient]] additive in [[fertilizer]]s.<ref name=PubChem/> Trade names include '''Bora-Care''', '''Borathor''', '''Termite Prufe''', '''Board Defense''', '''Polybor''',<ref name=Polybor/> '''Tim-bor''',<ref name=Tim-bor/> and '''Can-Bor'''.

==Preparation==

The anhydrous form can be crystallized from a molten mixture of [[sodium oxide]] {{chem2|Na2O}} and [[boric oxide]] {{chem2|B2O3}}.<ref name=leed1977/>

==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 {{convert|30|C|K}}.<ref name=brig2001/>

===Structure===

The [[anhydrous]] salt exists in two stable crystalline forms, α and β.<ref name=rubn2009/><ref name=penin2002/>

The α form has [[monoclinic crystal structure]], with the P2_1/a space group. The unit cell parameters at 273 [[kelvin|K]] are: ''a'' = 650.7 [[picometre|pm]], ''b'' = 1779 pm, ''c'' = 837.7 pm, β = 96.6 °, ''Z'' = 4. The structure contains two interlocking boron-oxygen frameworks, each of them consisting of alternating single and double rings composed of two triangles and a tetrahedron, the so called triborate and pentaborate groups. The two frameworks are connected by two (non-equivalent) sodium atoms, each surrounded by 8 oxygens, comprising finite chains of four {{chem2|NaO8}} polyhedra with shared edges. The thermal expansion is sharply anisotropic, including negative thermal expansion. The thermal expansion tensor in 273–1000 K in function of absolute temperature ''T'' has α₁₁ = 55–0.042''T'', α₂₂ = 11, α₃₃ = -15 + 0.032''T'' (×10–6) K⁻¹, μ = (c^α₃₃) = 42°.<ref name=rubn2009/>

The β form has monoclinic crystal structure, with the P2_1/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 {{chem2|[B8O13](2−)}} formed by six {{chem2|BO3}} triangles (Δ) and two {{chem2|BO4}} tetrahedra (T), which can be viewed as a {{chem2|B5O10}} group linked to a {{chem2|B3O7}} group. This fundamental building block is identical to that of the α form and of [[silver octaborate]] {{chem2|Ag2B8O13}}, with some subtle differences.<ref name=penin2002/>

==Uses==

Dilute solutions of disodium octaborate are sprayed on wood surfaces to kill [[termite]]s, [[powder post beetle]]s, [[carpenter ant]]s, fungi and algae. The tetrahydrate is also available as pellets for embedding in structural wood. Compared to other chemicals used for these purposes, it has the advantages of lack of odor, permanent effect, and low toxicity to humans and pets.<ref name=NIH/>

The compound was also shown to significantly reduce [[dust mite]] populations in the home when applied as a dilute solution to carpets and upholstery together with regular [[vacuum cleaner|vacuum cleaning]].<ref name=codi2003/>

Disodium octaborate, applied to the soil or [[Foliar feeding|foliar spray]], has been shown to inhibit pests of crops such as [[tomato]] and [[pistachio]], with no observed detrimental effects to the plants.<ref name=kava2017/><ref name=acar2016/>

==Safety==

Disodium octaborate is neither flammable, nor combustible or explosive and has low acute oral and dermal toxicity.<ref name=nany1998/> The oral 50% lethal doses (LD50) are 5.3 g/kg for guinea pig, 2g/kg for rats.<ref name=NIH/> 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.<ref name=ECHA2018/>

<references>

<ref name=ECHA2018>"[https://echa.europa.eu/documents/10162/d52fda04-9460-5bac-1bb7-aad4ec9c4960 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.</ref>

<ref name=Polybor>"[https://www.borax.com/products/polybor Polybor]". Product data page at the U. S. Borax company website. Accessed on 2022-06-27.</ref>

<ref name=Tim-bor>"[https://www.borax.com/products/tim-borTim-bor ]{{Dead link|date=February 2024 |bot=InternetArchiveBot |fix-attempted=yes }}". Product data page at the U. S. Borax company website. Accessed on 2022-06-27.</ref>

<ref name=codi2003>{{cite journal | doi = 10.1034/j.1398-9995.2003.00100.x| title = Disodium octaborate tetrahydrate (DOT) application and vacuum cleaning, a combined strategy to control house dust mites| year = 2003| last1 = Codina| first1 = R.| last2 = Lockey| first2 = R. F.| last3 = Diwadkar| first3 = R.| last4 = Mobly| first4 = L. L.| last5 = Godfrey| first5 = S.| journal = Allergy| volume = 58| issue = 4| pages = 318–324| pmid = 12708980| s2cid = 21252903}}</ref>

<ref name=brot1994>B.J Brotherton Boron: Inorganic Chemistry Encyclopedia of Inorganic Chemistry (1994) Ed. R. Bruce King, John Wiley & Sons {{ISBN|0-471-93620-0}}</ref>

<ref name=nany1998>{{cite journal | doi = 10.1023/A:1009684821954| title = A review of subterranean termite control practices and prospects for integrated pest management programmes | year = 1998| last1 = Su| first1 = NAN-YAO| last2 = Scheffrahn| first2 = Rudolf H.| journal = Integrated Pest Management Reviews| volume = 3| pages = 1–13| s2cid = 59039873}}</ref>

<ref name=NIH>"[https://chem.nlm.nih.gov/chemidplus/rn/12008-41-2 Disodium octaborate]". Substance page at the National Institutes of Health - National Library of Medicine ''ChemDplus'' website. Accessed on 2022-06-28.</ref>

<ref name=PubChem>"[https://pubchem.ncbi.nlm.nih.gov/compound/90479350 Boron sodium oxide (B8Na2O13)]". Substance page at the ''PubChem'' website. Accessed on 2022-06-28.</ref>

<ref name=brig2001>M. Briggs (2001): "Boron Oxides, Boric Acid, and Borates". Chapter of the ''Kirk-Othmer Encyclopedia of Chemical Technology''. Wiley.</ref>

<ref name=scher2008>H. W. Scherer et al (2008): "Fertilizers". Chapter of ''Ullmann's Encyclopedia of Industrial Chemistry'', 7th ed.</ref>

<ref name=rubn2009>{{cite journal | doi = 10.1524/zkri.217.9.444.22881| title = Thermal behaviour of the rigid boron-oxygen groups in the α-Na2B8O13 crystal structure| year = 2002| last1 = Bubnova| first1 = R. S.| last2 = Shepelev| first2 = Ju. F.| last3 = Sennova| first3 = N. A.| last4 = Filatov| first4 = S. K.| journal = Zeitschrift für Kristallographie - Crystalline Materials| volume = 217| issue = 9| pages = 444–450| bibcode = 2002ZK....217..444B| s2cid = 95388918}}</ref>

<ref name=penin2002>{{cite journal | doi = 10.1006/jssc.2002.9704| title = Crystal Structure of a New Form of Sodium Octoborate β-Na2B8O13| year = 2002| last1 = Penin| first1 = N.| last2 = Touboul| first2 = M.| last3 = Nowogrocki| first3 = G.| journal = Journal of Solid State Chemistry| volume = 168| issue = 1| pages = 316–321| bibcode = 2002JSSCh.168..316P}}</ref>

<ref name=leed1977>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.</ref>

<ref name=kava2017>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).</ref>

<ref name=acar2016>{{cite journal | doi = 10.3906/tar-1511-80| title = Boron affects the yield and quality of nonirrigated pistachio (Pistacia vera L.) trees| year = 2016| last1 = Açar| first1 = İzzet| last2 = Doran| first2 = İlhan| last3 = Aslan| first3 = Nevzat| last4 = Doğruer Kalkanci| first4 = Nilgün| journal = Turkish Journal of Agriculture and Forestry| volume = 40| pages = 664–670| url = https://dergipark.org.tr/tr/pub/tbtkagriculture/issue/34745/384233| doi-access = free}}</ref>

</references>

{{Borates}}

[[Category:Borates]]

[[Category:Sodium compounds]]