POPOP
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 447082693
| ImageFile=POPOP.svg
| ImageSize=200px
| PIN=2,2′-(1,4-Phenylene)bis(5-phenyl-1,3-oxazole)
| OtherNames=POPOP
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo=1806-34-4
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = MDI740G2Q0
| PubChem=15732
| SMILES=C1=CC=C(C=C1)C2=CN=C(O2)C3=CC=C(C=C3)C4=NC=C(O4)C5=CC=CC=C5
| EINECS = 217-304-6
| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}
| ChemSpiderID = 14960
| InChI = 1/C24H16N2O2/c1-3-7-17(8-4-1)21-15-25-23(27-21)19-11-13-20(14-12-19)24-26-16-22(28-24)18-9-5-2-6-10-18/h1-16H
| InChIKey = MASVCBBIUQRUKL-UHFFFAOYAO
| StdInChI_Ref = {{stdinchicite|changed|chemspider}}
| StdInChI = 1S/C24H16N2O2/c1-3-7-17(8-4-1)21-15-25-23(27-21)19-11-13-20(14-12-19)24-26-16-22(28-24)18-9-5-2-6-10-18/h1-16H
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
| StdInChIKey = MASVCBBIUQRUKL-UHFFFAOYSA-N
| RTECS =
| MeSHName =
| ChEBI_Ref = {{ebicite|changed|EBI}}
| ChEBI = 52236
}}
|Section2={{Chembox Properties
| Formula=C24H16N2O2
| MolarMass=364.40 g/mol
| Appearance=
| Density=
| MeltingPt=
| BoilingPt=
| Solubility=
}}
|Section3={{Chembox Hazards
| MainHazards=
| FlashPt=
| AutoignitionPt =
}}
}}
POPOP or 1,4-bis(5-phenyloxazol-2-yl) benzene is a scintillator. It is used as a wavelength shifter (also called a "secondary scintillator"), which means that it converts shorter wavelength light to longer wavelength light. Its output spectrum peaks at 410 nm, which is violet.[http://nationaldiagnostics.com/article_info.php/articles_id/117?osCsid=0f352a9e0b698613ea3618c7e086941a Mechanism of Liquid Scintillation Counting], National Diagnostics, retrieved 24 Sept 2007 POPOP is used in both solid and liquid organic scintillators.