A Huntsman Corp. individual investor has sued Hexion Specialty Chemicals Inc., saying she was defrauded when the Apollo Management LP unit backed out of an agreement to buy Huntsman.

Hexion engaged in a scheme that "deceived the investing public regarding Hexion's efforts and intentions with respect to the merger with Huntsman," Sandra Lifschitz said in her complaint filed Thursday in federal court in New York.

Lifschitz seeks class-action, or group, status on behalf of investors who bought Huntsman's common shares between May 14 and June 18. The fraud caused those investors to buy the shares at "artificially inflated prices," according to the complaint. Hexion sued Salt Lake City-based Huntsman June 18 to cancel their $6.54 billion merger, saying the combined company would be insolvent.

Lifschitz's lawsuit "has no merit, and we will defend against it vigorously," Hexion spokesman Jonathan Gasthalter said.

Hexion's lawsuit seeking to end its $28-a-share offer for Huntsman is scheduled to go to trial on Sept. 8 in the Delaware Chancery Court in Wilmington.