Stable polymorph of morphine

In the stable polymorph of the title compound, C₁₇H₁₉NO₃ [systematic name: (5α,6α)-7,8-didehydro-4,5-ep­oxy-17-methyl­morphinan-3,6-diol], the mol­ecular conformation is in agreement with the characteristics of previously reported morphine forms. The molecule displays the typical T-shape and its piperidine ring adopts a slightly distorted chair conformation. Inter­molecular O—H...O hydrogen bonds link the mol­ecules into helical chains parallel to the b axis. Intra­molecular O—H...O hydrogen bonds are also observed.