“Tetrahydroxyborate”的意思、由来-开放百科全书

词条

Tetrahydroxyborate

释义

Chemical properties
Basicity Structure Chemical reactions
Production
Uses
Occurrence
See also
References

{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 470604503
| ImageFileL1 = Tetrahydroxyborate-2D-dimensions.png
| ImageFileL1_Ref = {{chemboximage|correct|??}}
| ImageSizeL1 =
| ImageNameL1 = Stereo, skeletal formula of tetrahydroxyborate with a dimension
| ImageFileR1 = Tetrahydroxyborate-anion-from-sodium-salt-xtal-3D-balls.png
| ImageFileR1_Ref = {{chemboximage|correct|??}}
| ImageSizeR1 =
| ImageNameR1 = Ball and stick model of tetrahydroxyborate
| IUPACName = Tetrahydroxyborate
| SystematicName = Tetrahydroxyboranuide^[1] (substitutive)

Tetrahydroxidoborate(1-)^[1] (additive)

|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|changed|??}}
| CASNo = 15390-83-7
| PubChem = 177595
| ChemSpiderID = 154612
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 41132
| ChEMBL = 1231419
| ChEMBL_Ref = {{ebicite|changed|EBI}}
| Gmelin = 1966
| SMILES = O[B-](O)(O)O
| StdInChI = 1S/BH4O4/c2-1(3,4)5/h2-5H/q-1
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = KCFLOKKYWBPKFN-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
}}
|Section2={{Chembox Properties
| Formula = H₄BO₄⁻
| MolarMass = 78.840 g mol⁻¹
}}
}}

Tetrahydroxyborate (systematically named tetrahydroxyboranuide and tetrahydroxidoborate(1−)) is an inorganic anion with the chemical formula {{Chem|[B(OH)|4|]|−}} (also written as {{Chem|B(OH)|4|−}} or {{Chem|BH|4|O|4|−}}). It contributes no colour to tetrahydroxyborate salts. It is found in the mineral hexahydroborite, Ca(B(OH)₄)₂{{hydrate|2}} (originally formulated CaB₂O₄{{hydrate|6}}).^[2] It is classified as a weak base.

Chemical properties

Basicity

Tetrahydroxyborate can assimilate a proton into the anion by recombination:

{{NumBlk|:|{{big|{{Chem|B(OH)|4|−}} + {{H+}} → {{Chem|B(OH)|3}} + {{H2O}}}}|{{EquationRef|1}}}}

Because of this capture of a proton ({{Chem|H|+}}), tetrahydroxyborate has Arrhenius-basic character. Its protonation product is boric acid. In aqueous solution, most tetrahydroxyborate ions are undissociated.{{Citation needed|reason=boric acid to tetrahydroxyborate pK = 9.14 |date=March 2016}}

{{NumBlk|:|{{big|{{Chem|B(OH)|4|−}}}} {{EqmL}} {{big|{{Chem|B(OH)|3}} + {{OH-}}}}|{{EquationRef|2}}}}

Structure

It is a boron oxoanion with a tetrahedral geometry.^[3] It is isoelectronic with the hypothetical compound orthocarbonic acid.

Chemical reactions

Tetrahydroxyborate undergoes the typical chemical reactions of a hydroxyborate. Upon treatment with a standard acid, it converts to boric acid and a metal salt. Oxidation of tetrahydroxyborate gives perborate. When heated to a high temperature, tetrahydroxyborate salts decompose to produce metaborate salts and water, or to produce boric acid and a metal hydroxide:

n [B(OH)₄]⁻ → (BO{{Su|b=2|p=−}})_n + 2n {{H2O}}

[B(OH)₄]⁻ → B(OH)₃ + HO⁻

Production

Tetrahydroxyborate is produced by boric acid alkalinisation. In this process boric acid and hydroxide anions react to produce tetrahydroxyborate according to the following reaction:

B(OH)₃ + HO⁻ → [B(OH)₄]⁻

This process also involves aquatrihydroxyboron as an intermediate, and occurs in two steps. No catalyst is needed for alkalinisation (step 2).

B(OH)₃ + {{H2O}} → [B(OH)₃H₂O]
[B(OH)₃H₂O] + HO⁻ → [B(OH)₄]⁻ + {{H2O}}

Catalytic amounts of water are used for the process. By altering the process conditions, other borate anions may also be produced on the same production site.

Uses

Tetrahydroxyborate can be used as a cross-link in polymers.

Occurrence

The tetrahydroxyborate anion is found in Na[B(OH)₄],^[4] Na₂[B(OH)₄]Cl and Cu^II[B(OH)₄]Cl.

References

1. ^¹{{Cite web|title = Tetrahydroxoborate(1-) (CHEBI:41132)|url = https://www.ebi.ac.uk/chebi/searchId.do?chebiId=41132|work = Chemical Entities of Biological Interest (ChEBI)|location = UK|publisher = European Bioinformatics Institute}}
2. ^Glossary of Geology,5th edition, 2005, {{ISBN|978-0922152766}} ed. by Julia A. Jackson, James P. Mehl, Klaus K. E. Neuendorf, American Geological Institute
3. ^{{Greenwood&Earnshaw|page=203–205}}
4. ^{{ cite journal | journal = Acta Crystallogr. C | volume = 49 | issue = 6 |date=June 1993 | pages = 1039–1041 | title = Structure of sodium tetrahydroxyborate |author1=L. J. Csetenyi |author2=F. P. Glasser |author3=R. A. Howie | doi = 10.1107/S0108270193000058 }}

2 : Borates|Anions

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