The concert last night at the Library of Congress by violinist Igor Ozim and panist Ilse von Alpenheim spanned a wide range of styles Mozart, Beethoven and Richard Strauss. But it did not tap a comparable range of expression.

Thus the program was a bit much of a muchness. Neither the Mozart, the G major Sonata (K. 379), nor the Beethoven, the E flat major Sonata (op. 12, No. 3) represents its composer at his most eloquent.

Consisting of only tow movements, the Mozart is a curiousity. Its first movement lacks a really sharp profile, but the longer theme and variations that follows is more ambitious. One variation with bold leaps in both instruments was followed in both instruments was followed by an intimate section, after which there was a delicate variation with the violin playing pizzicato. The Beethoven is decidedly more extroverted.

Both works give relatively equal voices to each instrument. Of the two performers, it was von Alpenheim who was the more polished and assertive in these works. Ozim played poetically, but his tone was short on resonance.

In the Richard Strauss Sonata after the intermission Ozim's tone was bigger, with the high notes finally singing out. It is an early work and lacks the overwhelming urgency of expression, though, that woudl become so characteristic of Strauss. The sonata is not bad, but its technical intricacies sometimes seem hardly worth the considerable physical effort they demand.

It was a brief encore that was most communicative. It was Schumann's Romance, Clara Schumann's, that is. She was famous as the wife of Robert Schumann, the mother-confessor of Brahms and one of the great pianists of the 19th century. But her compositional skills were less renowned.

Though Ozim is hardly known here, von Alpenheim was a familiar performer and face during the splendid days when her husband, Antal Dorati, directed the National Symphony. He was in the audience last night.