Alpha chord
The alpha chord is a name given to a dissonant, almost-cluster like “extended” chord used frequently in Bela Bartok’s music.[1] It has the following scale degree spelling:
1 b3 b5 bb7 7 2 4 b6
This chord can be described as the polychord
However, this implies that there is a tonic, which may not be the case in a context where this chord is used.
The chord can be derived from an octatonic scale starting with a semitone. If the notes of an octatonic scale correspond to the numbers 1 - 8 then the alpha chord can be written as 2 4 6 8 1 3 5 7.
As a more concrete example, if we use an octatonic scale (initial semitone) starting on C then we would get the chord:
This is damn near impossible to read, so this is what it looks like enharmonically spelt:
The name was arbitrarily chosen.[1]
References:
[1]: lendvai-1971 p.42