X-Ray Structure of Aspirin

There is a second type of dimer in the crystal structure of aspirin. In this dimer the carbonyl groups of two adjacent esters are aligned perfectly anti-parallel for maximum dipole-dipole attraction! Rotate the structure until you see just how perfectly these carbonyls line up in a Newman perspective!

Figure. The X-ray structure of aspirin contains dimers formed by dipole-bonding between two ester functions.

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