:Barium metaphosphate

{{distinguish|barium phosphate}}

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| ImageFile = Barium metaphosphate.svg

| ImageSize = 180px

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| IUPACName = barium(2+); dioxido(oxo)phosphanium

|Section1={{Chembox Identifiers

| CASNo = 13762-83-9

| CASNo_Ref = {{Cascite|changed|CAS}}

| ChemSpiderID = 2341276

| PubChem = 3084168

| EINECS = 237-362-6

| StdInChI=1S/Ba.2HO3P/c;2*1-4(2)3/h;2*(H,1,2,3)/q+2;;/p-2

| StdInChIKey = XNJIKBGDNBEQME-UHFFFAOYSA-L

| SMILES = [O-][P+](=O)[O-].[O-][P+](=O)[O-].[Ba+2]

}}

|Section2={{Chembox Properties

| Formula = Ba(PO₃)₂

| MolarMass = 295.27 g/mol

| Appearance = Powder{{cite web|url=http://www.americanelements.com/barium-metaphosphate.html|title=Barium Metaphosphate|first=American|last=Elements|website=American Elements|accessdate=17 April 2018}}

| Density = 3.63 g/cm³

| MeltingPtC = 1560{{cite web|url=http://www.chemicalbook.com/ChemicalProductProperty_EN_CB2329833.htm|title=BARIUM METAPHOSPHATE - 13762-83-9|website=www.chemicalbook.com|accessdate=17 April 2018}}

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Barium metaphosphate is an inorganic substance with the molecular formula Ba(PO₃)₂. It is a colourless solid that is insoluble in water, though is soluble in acidic solutions through "slow dissolution".{{Cite web|url=http://www.chemicalbook.com/ChemicalProductProperty_EN_CB2329833.htm|title=Barium Metaphosphate|date=2017|website=Chemical Book|access-date=November 27, 2017}} X-ray crystallography shows that this material is composed of Ba²⁺ cations attached to a polyphosphate ((PO₃⁻)_n) anion."Form of barium metaphosphate" Grenier, Jean C.; Martin, Claude M.; Durif, Andre; Tran Qui Duc; Guitel, J. C. Bulletin de la Société Francaise de Minéralogie et de Cristallographie (1967), vol. 90, 24-31. A number of hydrated forms are known which are actually cyclic metaphosphates, Ba₂(P₄O₁₂)·3.5H₂O, Ba₃(P₃O₉)₂·6H₂O.{{cn|date=September 2023}}

File:PolyphosphateChainP4.png anion.]]