phthalazine

{{chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 440002476

| Reference =Merck Index, 11th Edition, 7344.

| ImageFile = Phthalazin - Phthalazine.svg

| ImageSize = 180

| ImageAlt = Skeletal formula of phthalazine

| ImageFile1 = Phthalazine-3D-balls.png

| ImageSize1 = 180

| ImageAlt1 = Ball-and-stick model of the phthalazine molecule

| PIN = Phthalazine{{cite book | title = Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book) | publisher = The Royal Society of Chemistry | date = 2014 | location = Cambridge | page = 212 | doi = 10.1039/9781849733069-FP001 | isbn = 978-0-85404-182-4}}

| OtherNames = Benzo-orthodiazine
2,3-Benzodiazine
Benzo[d]pyridazine

|Section1={{Chembox Identifiers

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

| CASNo=253-52-1

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = 91Y28DM24N

| PubChem = 9207

| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}

| ChemSpiderID = 8852

| SMILES = C1=CC=C2C=NN=CC2=C1

| InChI = 1/C8H6N2/c1-2-4-8-6-10-9-5-7(8)3-1/h1-6H

| InChIKey = LFSXCDWNBUNEEM-UHFFFAOYAE

| StdInChI_Ref = {{stdinchicite|changed|chemspider}}

| StdInChI = 1S/C8H6N2/c1-2-4-8-6-10-9-5-7(8)3-1/h1-6H

| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}

| StdInChIKey = LFSXCDWNBUNEEM-UHFFFAOYSA-N

}}

|Section2={{Chembox Properties

| C=8|H=6|N=2

| Appearance = Pale yellow needles

| Density=

| MeltingPtC = 90 to 91

| BoilingPtC = 315 to 317

| BoilingPt_notes= (decomposition)

| Solubility = Miscible

| pKa=3.39Brown, H.C., et al., in Baude, E.A. and Nachod, F.C., Determination of Organic Structures by Physical Methods, Academic Press, New York, 1955.

}}

|Section3={{Chembox Hazards

| MainHazards=

| FlashPt=

| AutoignitionPt =

}}

}}

Phthalazine, also called benzo-orthodiazine or benzopyridazine, is a heterocyclic organic compound with the molecular formula C₈H₆N₂. It is isomeric with other naphthyridines including quinoxaline, cinnoline and quinazoline.