Measurements of the Raman and infrared spectra of salts containing the trimeric meta-anions M3O9n–(M = P, As, Si) suggest that the rings have the “chair”C3v configuration in the solid state and also, in the case of P3O93–, in aqueous solution. Similar studies were carried out on the tetrameta-species M4O124–(M = P, As, V).