Boron phosphate
{{Short description|Chemical compound}}
{{Use dmy dates|date=November 2023}}
{{Chembox
| ImageFile =
| ImageSize =
| IUPACName = Boron phosphate
| SystematicName=2,4,5-trioxa-1λ5-phospha-3-borabicyclo[1.1.1]pentane 1-oxidepubchem.ncbi.nlm.nih.gov/compound/83329#section=IUPAC-Name&fullscreen=true
| OtherNames =
|Section1={{Chembox Identifiers
| CASNo = 13308-51-5
| PubChem = 83329
| ChemSpiderID = 75189
| SMILES = B12OP(=O)(O1)O2
| InChI = 1/B.H3O4P/c;1-5(2,3)4/h;(H3,1,2,3,4)/q+3;/p-3
| InChIKey = YZYDPPZYDIRSJT-DFZHHIFOAS
| StdInChI = 1S/B.H3O4P/c;1-5(2,3)4/h;(H3,1,2,3,4)/q+3;/p-3
| StdInChIKey = YZYDPPZYDIRSJT-UHFFFAOYSA-K
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|Section2={{Chembox Properties
| Formula = BPO4
| MolarMass = 105.78 g/mol
| Appearance =
| Density = 2.52 g/cm3
| MeltingPt =
| BoilingPt =
| Solubility =
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|Section3={{Chembox Hazards
| ExternalSDS = [https://www.alfa.com/en/msds/?language=EN&subformat=AGHS&sku=32562 External SDS]
| NFPA-H = 2
| NFPA-F = 0
| NFPA-R = 0
| NFPA-S =
| NFPA_ref = [https://datasheets.scbt.com/sc-227516.pdf Boron phosphate] datasheets.scbt.com
| GHSPictograms = {{GHS07}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|302}}
| PPhrases = {{P-phrases|264|270|301+312|330|501}}
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Boron phosphate is an inorganic compound with the chemical formula BPO4. The simplest way of producing it is the reaction of phosphoric acid and boric acid. It is a white infusible solid that evaporates above 1450 °C.Corbridge DEC 2013, Phosphorus: Chemistry, Biochemistry and Technology, 6th ed., CRC Press, Boca Raton, Florida, {{ISBN|978-1-4398-4088-7}}
Synthesis
Boron phosphate is synthesized from phosphoric acid and boric acid at a temperature range from 80 °C to 1200 °C. The relatively cold treatment produces a white amorphous powder, which is converted to a microcrystalline product when heated at about 1000 °C for 2 hours.{{cite journal|doi=10.1002/cber.19040370171|title=Ueber die Bestimmung der Borsäure als Phosphat|year=1904|last1=Mylius|first1=F.|last2=Meusser|first2=A.|journal=Berichte der Deutschen Chemischen Gesellschaft|volume=37|pages=397–401|url=https://zenodo.org/record/1426102}}
The main reaction of the process is:
:H3BO3 + H3PO4 → BPO4 + 3 H2O
New ways of synthesizing the compound have also been reported, such as hydrothermal and microwave synthesis.{{cite journal|author=Baykal, A|author2=Kizilyalli, M|author3=Toprak, Muhammet S.|author4=Kniep, R|name-list-style=amp |year=2001|title=Hydrothermal and microwave synthesis of boron phosphate, BPO4|journal=Turkish Journal of Chemistry|volume=25|issue=4|pages=425–432}}
Due to the particular industrial interest of boron phosphate, other methods are used as well:
- Phosphoric acid and triethyl borate
- Triethyl phosphate and boron trichloride
- Diammonium phosphate acid and borax heated to 1000 °C
- Boric acid and phosphorus pentoxide (hydrothermal)
Structure
If obtained at pressure, the ordinary structure is isomorphous with the β-cristobalite, while subjecting it to high pressure is obtained a compound isomorphic with α-quartz.{{cite journal|doi=10.1107/S0365110X5900024X|title=New high pressure modifications of BPO4 and BAsO4|year=1959|last1=MacKenzie|first1=J. D.|last2=Roth|first2=W. L.|last3=Wentorf|first3=R. H.|journal=Acta Crystallographica|volume=12|issue=1 |pages=79|bibcode=1959AcCry..12...79M |doi-access=free}} The structure of AlPO4, berlinite, is isomorphous with α-quartz.
Applications
It is used as a catalyst for dehydration and other reactions in organic synthesis. Also, it serves as a source of phosphates for exchange reactions in the solid state to obtain metal phosphates.{{cite journal|doi=10.1139/v65-222|title=Surface Chemistry and Catalytic Properties of Boron Phosphate: 1. Surface Area and Acidity|year=1965|last1=Moffat|first1=J. B.|last2=Goltz|first2=H. L.|journal=Canadian Journal of Chemistry|volume=43|issue=6|pages=1680}}