So I am almost finished with my harmonic analysis of Rondo a Capriccio. But I came across a mysterious chord. I'm trying to figure it out. Here is the chord:
I know from looking at it carefully, that it is an augmented sixth chord. I can rule out the Italian augmented sixth because there are 4 different notes in the augmented sixth. This leaves me with the French augmented sixth and the German augmented sixth as possibilities. I'm leaning on German but I will go through the chord possibilities systematically starting with German augmented sixths.
Here are the German augmented sixths on each possible root note:
X: T: Augmented sixth possibilities T: German C: Cheyanna Marie Ward M: 4/4 L: 1/4 K: G major % % V:1 clef=treble % % [V:1][A^ce^^f]4 |[_C_E_GA]4 |[_EG_B^c]4 |[_G_B_de]4 |]
And here are the French augmented sixths on each possible root note:
X: T: Augmented sixth possibilities T: French C: Cheyanna Marie Ward M: 4/4 L: 1/4 K: G major % % V:1 clef=treble % % [V:1][Ac_e_g]4 |[_CEF_A]4 |[_E_GAc]4 |[_G__Bc_e]4 |]
Looks like it is a Cb German Augmented Sixth. The chord before it is E major and the chord afterwards is Eb major which then gets tonicized for a few bars. The augmented sixth in the chord resolves to Bb in octaves. The Eb stays put as a common tone. The Gb moves up to G. But this means the augmented sixth resolves straight to tonic instead of to the expected Bb major chord. Here are the next few bars in the piece after the augmented sixth:
As you can see here, the resolution chord of Eb is tonicized for a few bars after the augmented sixth.
Can an augmented sixth lead straight to the tonic without a V I motion following the augmented sixth?