sentences:  It is named after the German chemist Eduard Zintl who investigated them in the 1930s, with the term "Zintl Phases" first used by Laves in 1941.Zintl phases are a subgroup of brittle, high-melting intermetallic compounds which are diamagnetic or exhibit temperature-independent paramagnetism, and are poor conductors or semiconductors.Zintl noted that there was an atomic volume contraction when these compounds were formed and realised this could indicate cation formation.