Half diminished scale
The half diminished scale is a seven-note musical scale. It is more commonly known as the Locrian 2 scale or the Aeolian 5 scale, names that avoid confusion with the diminished scale and the half-diminished seventh chord (minor seventh, diminished fifth). It is the sixth mode of the ascending melodic minor scale. In the key of B, the half-diminished scale built on C is associated with Cm75, which functions as a ii7 chord in minor (see chord-scale system). References

Heptatonic scales
Modes (music)
Hemitonic scales
Tritonic scales