Complex sentence: Zyklon B (also spelled Cyclon B or Cyclone B) was the trade name of a cyanide-based pesticide invented in the early 1920s and infamous for its later use by Nazi Germany to kill human beings in gas chambers of extermination camps during the Holocaust.
Split into simpler sentences: Zyklon B (also spelled Cyclon B or Cyclone B) was the trade name of a cyanide-based pesticide invented in the early 1920s. It is better known as to be used by Nazi Germany to kill human beings in gas chambers of extermination camps during the Holocaust.