Notes: C, D, Eb, E, F, G, Ab, A, Bb, and B - Key: C - Category: Undecatonic or Hendecatonic Scales
The C Major/Minor mixed uses eleven notes per octave. Because of this same reason it is a member of the so called Undecatonic or Hendecatonic -scales that have Eleven-note (or Eleven-tone). On the piano keyboard, it is made up of three black keys: Eb, Ab, and Bb and seven white keys: C, D, E, F, G, A, and B. This combination makes this scale - as well as the C Prometheus, C Prometheus Liszt, and C Prometheus Neapolitan - as great choices for composing or improvising music.
If we take a look a the key signature of the C Major/Minor mixed Scale we can find it has three flats and no sharps. Therefore, on sheet music you will find three accidentals on the score. The notes of this scale are: C, D, Eb, E, F, G, Ab, A, Bb, and B.