?2,5-Dihydroxy-1,4-dithiane , its cas register number is 40018-26-6. It also can be called?2,5-Dihydroxy-1,4-dithiane ; 1,4-Dithiane-2,5-diol ; 4-Dithiane-2,5-diol .It is a?white to yellowish crystalline powder.