Disodium hydrogen phosphite

{{Chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 436973042

| ImageFile = Disodium hydrogen phosphite.png

| ImageSize = 150px

| ImageAlt = Skeletal formula of disodium hydrogen phosphite

| ImageFile1 =

| ImageSize1 = 250

| ImageAlt1 = Ball-and-stick model of the component ions of disodium hydrogen phosphite

| IUPACName = sodium phosphonate pentahydrate

| OtherNames = Sodium phosphate dibasic pentahydrate,
sodium phosphite

|Section1={{Chembox Identifiers

| index1_label = anhydrous

| index2_label = pentahydrate

| InChI = 1/2Na.O3P/c;;1-4(2)3/q2*+1;-3/p+1

| InChIKey = XWGAABYWOLJBFF-IKLDFBCSAK

| SMILES1 = [H+].[Na+].[Na+].[O-]P([O-])[O-]

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/2Na.O3P/c;;1-4(2)3/q2*+1;-3/p+1

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = XWGAABYWOLJBFF-UHFFFAOYSA-O

| CASNo1_Ref = {{cascite|correct|CAS}}

| CASNo1 = 13708-85-5

| CASNo2_Ref = {{cascite|correct|CAS}}

| CASNo2 = 13517-23-2

| UNII1_Ref = {{fdacite|correct|FDA}}

| UNII1 = X65D416703

| UNII2_Ref = {{fdacite|correct|FDA}}

| UNII2 = UM5UZ43YVE

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID=21106436

| PubChem1 = 16211071

| PubChem2 = 22463763

| SMILES = O=P([O-])([O-])[H].[Na+].[Na+]

}}

|Section2={{Chembox Properties

| Na=2 | H=1 | P=1 | O=3

| Appearance = white solid

| Density =

| MeltingPt =

| BoilingPt =

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|Section3={{Chembox Hazards

| MainHazards =

| FlashPt =

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Disodium hydrogen phosphite is the name for inorganic compounds with the formula Na₂HPO₃•(H₂O)_x. The commonly encountered salt is the pentahydrate.{{cite journal|title=Zur Kenntnis der Hydrate des Na₂PHO₃, Phasenbeziehungen und kristallographische Untersuchungen (Hydrates of sodium phosphite, phase relations and crystallographic studies)|author1=Brodalla, Dieter |author2=Goeters, Christiane |author3=Kniép, Ruediger |author4=Mootz, Dietrich |author5=Wunderlich, Hartmut |journal=Zeitschrift für Anorganische und Allgemeine Chemie|year=1978|volume=439|pages=265–74|doi=10.1002/zaac.19784390132}} A derivative of phosphorous acid (HP(O)(OH)₂), it contains the anion HPO₃²⁻. Its common name suggests that it contains an acidic hydrogen atom, as in sodium hydrogen carbonate. However, this name is misleading as the hydrogen atom is not acidic, being bonded to phosphorus rather than oxygen. The salt has reducing properties. It is white or colorless solid, and is little studied.