COLUMBUS, Ohio — Hexion Specialty Chemicals Inc. says it no longer thinks that it will be able to acquire fellow chemicals maker Huntsman Corp. because of the deterioration of Huntsman's finances.

Hexion, which is based in Columbus, Ohio, and controlled by an affiliate of Apollo Management LP, filed a lawsuit in the Delaware Court of Chancery to declare its contractual rights with respect to the $10.6 billion deal for the company, which is based in Salt Lake City but has its administrative headquarters in The Woodlands, Texas.

Hexion says it believes that the capital structure agreed to for the combined company is no longer viable because of Huntsman's higher debt and its lower-than-expected profits. Hexion says going forward with the acquisition with that capital structure would render the combined company insolvent.

Huntsman's first-quarter profit tumbled 84 percent on higher revenues. In late May, the company announced big price hikes and an energy surcharge to cover rising costs. Huntsman sells epoxy resins, polyurethanes and other specialty chemicals.

Hexion, which is controlled by an affiliate of Apollo Management LP, had planned to buy Huntsman for $6.5 billion in cash.