The Harris County Appraisal District has filed a motion in court asking a judge to order Exxon Mobil Corp. to release documents related to its sprawling campus near The Woodlands, the latest move in an ongoing legal dispute between HCAD and the oil giant over property taxes and the value of its new corporate home.

The motion, filed last week in state district court, outlines HCAD's unsuccessful efforts to seek information from Exxon Mobil affiliate Palmetto Transoceanic related to the land acquisition and related costs for the property west of Interstate 45 and north of the Grand Parkway.

"With no documents produced on Exxon Mobil's newly built corporate campus, the district's outside appraisers cannot appraise the subject property and the district cannot adequately defend this lawsuit," the motion said.

HCAD said it asked Palmetto for documents numerous times and signed a confidentiality agreement, but it has not received what it has been seeking.

Last fall, Exxon Mobil filed suit against the appraisal district protesting HCAD's $1.04 billion value placed on the oil giant's campus for 2015.

Irving-based Exxon Mobil, which has been highly guarded about the campus project, did not provide its own estimation of the property's value but claimed the actual value "is substantially below" what was assessed.

Exxon Mobil's campus was built to house some 10,000 workers. It is in the Springwoods Village master-planned community and is listed at 23125 North Freeway on the tax rolls.

Exxon Mobil declined to comment.