Tritone Scale

The tritone scale (also called the two-semitone tritone scale or Slonimsky's scale) is a symmetrical hexatonic scale built around the tritone interval. Two chromatic clusters — each consisting of two consecutive half steps — are placed a tritone apart. The result is tense and chromatic, with an unsettled quality that doesn't fit neatly into any conventional harmonic context. It appears in contemporary classical composition and avant-garde jazz where symmetric scale exploration is valued.

Construction

C tritone scale:
C — D♭ — D — F# — G — A♭ — C

Step pattern: H — H — A2 — H — H — A2
(A2 = augmented second / minor third = 3 semitones)

Formula: 1  ♭2  2  ♯4  5  ♭6

Six notes, divided into two identical groups of three:
  Cluster 1: C  D♭  D    (C, chromatic above, whole step above)
  Cluster 2: F# G   A♭   (tritone from C, chromatic above, half step above)

The two clusters are a tritone apart (C to F# = 6 semitones).

Symmetry

Like the whole tone and diminished scales, the tritone scale has limited transpositions due to its symmetry — the tritone divides the octave in half:

C tritone scale:   C  D♭  D  F#  G  A♭
F# tritone scale:  F# G   A♭  C  D♭  D  (same six notes)

Only six distinct tritone scales exist (one for each tritone-related pair of pitches).
A lick played in C will work unchanged in F# — same notes, same scale.

Contrast with:
  Whole tone: 2 distinct scales
  Diminished: 3 distinct scales
  Tritone:    6 distinct scales (less symmetric than whole tone or diminished)

Sound and Character

Chromatic, tense, unsettled. The consecutive half steps create small chromatic clusters at the bottom of each group, while the tritone gap creates maximal tonal distance between the two clusters. There's no clear harmonic context suggested — it doesn't point toward a major, minor, or dominant chord the way the whole tone scale points toward augmented dominants. It's more of a texture: a way of moving through pitch space with a consistent chromatic and symmetric feel.

Over Dominant Chords

C7 chord tones: C E G B♭
C tritone scale: C D♭ D F# G A♭

Chord tones in scale:
  C = root ✓
  G = 5th ✓
  E = not in scale (the major 3rd is missing)
  B♭ = not in scale (the ♭7 is missing)

The scale does NOT contain the chord's defining 3rd and 7th —
which means it doesn't clearly identify a C dominant chord.

More useful: think of it as providing colour notes (♭9, ♮2, ♯11, ♭6)
that can sit above a clearly stated dominant chord tone in the bass or inner voices.

Scale	Dominant alterations provided	Harmonic clarity
Tritone scale	♭9, ♮9, #11, ♮5, ♭13	Low — missing M3 and ♭7
Half-whole diminished	♭9, #9, #11, 13 (full set)	High — contains all chord tones + alterations
Altered scale	♭9, #9, #11, ♭13 (full set)	High — contains M3, ♭7 + all alterations
Whole tone	#11, #5	Medium — contains M3 and ♭7

Historical Context

Nicolas Slonimsky catalogued this and hundreds of other scale patterns in his 1947 Thesaurus of Scales and Melodic Patterns — one of the most comprehensive inventories of scalar possibilities ever compiled. Coltrane used Slonimsky's Thesaurus as a practice resource during his "sheets of sound" period. The tritone scale appears in the Thesaurus among the symmetric patterns. In contemporary composition, it surfaces in works that treat all twelve pitches as equally available resources rather than as functional scale degrees.

References

• Slonimsky — Thesaurus of Scales and Melodic Patterns
• Liebman — A Chromatic Approach to Jazz Harmony and Melody
• musictheory.net ↗