Viennese trichord
| Component intervals from root | |
|---|---|
| tritone | |
| minor second | |
| root | |
| Tuning | |
| 8:12:17 | |
| Forte no. / | |
| 3-5 / | |
| Interval vector | |
| <1,0,0,0,1,1> | 
In music theory, a Viennese trichord (also known as Viennese fourth chord and tritone-fourth chord), named for the Second Viennese School, is a pitch set with prime form (0,1,6). Its Forte number is 3-5. The sets C–D♭–G♭ and C–F♯–G are both examples of Viennese trichords, though they may be voiced in many ways.
According to Henry Martin, "[c]omposers such as Webern ... are partial to 016 trichords, given their 'more dissonant' inclusion of ics 1 and 6."
In jazz and popular music, the chord formed by the inversion of the set usually has a dominant function, being the third, seventh, and added fourth/eleventh of a dominant chord with elided root (and fifth, see jazz chord). For example, the Viennese trichord of C-F#-G could be considered a D11/C: D (elided) - F# - A (elided) - C - G.
| Prime | Inverse | 
|---|---|
| 0,1,6 | 0,6,e | 
| 1,2,7 | 1,7,0 | 
| 2,3,8 | 2,8,1 | 
| 3,4,9 | 3,9,2 | 
| 4,5,t | 4,t,3 | 
| 5,6,e | 5,e,4 | 
| 6,7,0 | 6,0,5 | 
| 7,8,1 | 7,1,6 | 
| 8,9,2 | 8,2,7 | 
| 9,t,3 | 9,3,8 | 
| t,e,4 | t,4,9 | 
| e,0,5 | e,5,t |