Lawesson's reagent

Lawesson's reagent
Names
	IUPAC name 2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide
	Preferred IUPAC name 2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-dithione
	Other names Lawesson reagent; LR
Identifiers
CAS Number	19172-47-5 ;
3D model (JSmol)	Interactive image;
ChemSpider	79346 ;
ECHA InfoCard	100.038.944
EC Number	242-855-4;
PubChem CID	87949;
UNII	A4125MQ8RX ;
CompTox Dashboard (EPA)	DTXSID4066460 ;
	InChI InChI=1S/C14H14O2P2S4/c1-15-11-3-7-13(8-4-11)17(19)21-18(20,22-17)14-9-5-12(16-2)6-10-14/h3-10H,1-2H3 Key: CFHGBZLNZZVTAY-UHFFFAOYSA-N ; InChI=1/C14H14O2P2S4/c1-15-11-3-7-13(8-4-11)17(19)21-18(20,22-17)14-9-5-12(16-2)6-10-14/h3-10H,1-2H3 Key: CFHGBZLNZZVTAY-UHFFFAOYAB;
	SMILES S=P1(SP(=S)(S1)c2ccc(OC)cc2)c3ccc(OC)cc3;
Properties
Chemical formula	C14H14O2P2S4
Molar mass	404.45 g·mol−1
Appearance	Slightly yellow powder
Melting point	228–231 °C (442–448 °F; 501–504 K)
Solubility in water	Insoluble
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H261, H302, H312, H332
Precautionary statements	P231+P232, P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P312, P304+P340, P312, P322, P330, P363, P370+P378, P402+P404, P501
Related compounds
Related thiation agents	Hydrogen sulfide,; Phosphorus pentasulfide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Lawesson's reagent (LR) is a chemical compound used in organic synthesis as a thiation agent. Lawesson's reagent was first made popular by Sven-Olov Lawesson, who did not, however, invent it. Lawesson's reagent was first made in 1956 during a systematic study of the reactions of arenes with P₄S₁₀.