I would like to know of examples of augmented chords of type 5# (I do not refer to 6th) in classical music, I know the theory for the formation of this type of chords (C aug or C+ or C(5#)-> C, 3ª major interval -> E and 5ª augmented interval -> G#), I have learned many examples in popular music and jazz but I would like to know in as much detail as possible examples in classical music.
Before I start, note that oftentimes these "augmented triads" in classical music are not bonafide augmented triads but actually just dominants with a brief chromatic passing tone. But not always!
Now, there's really no better one-stop shop than this terrific minuet by Mozart (K 355). Here's a score, and below is a sample of the opening measures; check out the augmented triads in mm. 1, 5, 7, and 9. (Whether they truly "are" and function as augmented triads is a much longer discussion; but they do momentarily create augmented harmonies.)
And since I've got Wagner on the brain, here are some other ideas.
I've linked the music; I'll leave it up to you to find the scores:
- Wagner, Siegfried, Act I Scene 3 (beginning in m. 2430), at the famous "Nothung!" calls. The calls themselves are above an F augmented triad, and there's a brief intro that could be understood as a D augmented triad.
- Wagner, Siegfried, Act III Scene 2 (m. 440), as Siegfried confronts The Wanderer. The opening progression, in A flat, alternates between I and V+.
- Similarly, check out Beethoven's Op. 119 No. 1 Bagatelle in G minor. In m. 17, a V chord in A flat has a chromatic passing tone B-natural that briefly creates a V+.
Mozart used augmented triads in his sonata in A major (3rd variation for example).
Chopin used augmented triads in his prelude in e minor (augmented triad with a major 7th) and a full augmented triad in his prelude in c minor.