Ungewöhnliches Strukturmerkmal kristalliner Phthalsäure

✍ Scribed by Otto Ermer

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: German
• Weight: 427 KB
• Volume: 64
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19810640623

✦ Synopsis

Unusual Structural Feature of Crystalline Phthalic Acid

In crystalline phthalic acid the strain resulting from repulsion between the carboxylic groups is only partially relieved by rotating these groups out of the plane of the benzene ring around the (HOO)CC bonds. This is also achieved through a surprisingly large deviation of 20.3 (1)° from planarity of the (HOO)CCCC (OOH) torsion angle, as confirmed by an accurate redetermination of the crystal structure. This torsion angle may be smaller in the free molecule, i.e. packing forces appear at least partly responsible for its high value in the crystal.