IPCS
p-BENZOQUINONE. 0779. October 1997. CAS No: 106-51-4 ... p-BENZOQUINONE. IMPORTANT DATA. Physical State; Appearance. YELLOW CRYSTALS, WITH PUNGENT ODOUR. ...
http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc07/icsc0779.pdf