Green Cross (chemical warfare) The mixture was chlorine-phosgene, with 95% and 5%. Green Cross (chemical warfare) Green Cross (Grünkreuz) is a World War I chemical warfare pulmonary agent consisting of chloropicrin (PS, Aquinite, Klop), phosgene (CG, Collongite) and/or trichloromethyl chloroformate (Surpalite, Perstoff). Green Cross is also a generic World War I German marking for artillery shells with pulmonary agents (chemical payload affecting the lungs). The tip of the projectile with the fuse end painted green and a green cross at the bottom of the cartridge. Other Green Cross mixtures were based on phosgene and/or diphosgene. The first use of Green Cross was on May
Chemical element plants, the calcium in mollusc shells, or the iron in the hemoglobin in vertebrate animals' red blood cells. The concept of an "element" as an undivisible substance has developed through three major historical phases: Classical definitions (such as those of the ancient Greeks), chemical definitions, and atomic definitions. Ancient philosophy posited a set of classical elements to explain observed patterns in nature. These "elements" originally referred to "earth", "water", "air" and "fire" rather than the chemical elements of modern science. The term 'elements' ("stoicheia") was first used by the Greek philosopher Plato in about 360 BCE in his dialogue Timaeus,