The Marine Corps has scheduled the court-martial of Sgt. Clayton J. Lonetree, accused of passing secrets to the Soviet Union, for July 22 at Quantico Marine Base, the Defense Department said yesterday.

Lonetree, 25, was ordered last month to stand trial at a general court-martial on 13 charges, including one count of espionage.

A U.S. Embassy guard in Moscow in 1985 and 1986, he had been accused of 24 violations of the Uniform Code of Military Justice. But charges that he escorted Soviet agents through the embassy building last year were set aside for lack of evidence.

Lonetree is accused of passing classified documents stolen from the embassy to the Soviets. He also is charged with passing along the floor plans and office assignments for the U.S. embassies in Moscow and Vienna and with identifying to Soviet agents the U.S. intelligence operatives assigned to the Moscow embassy.

Meanwhile, officials said, Douglas Beane, a Marine accused of deserting from Vietnam in 1970, is not eligible for presidential clemency but could be dismissed from the service with virtually no punishment.

Beane, 39, voluntarily flew to the United States from Australia Tuesday to see his sick father in Vermont and is restricted at Quantico pending a military hearing.