How many chemicals are there?
There are a huge number of possible chemicals. Estimates range from 1018 to 10200. For comparison the number of grains of sand on the Earth is about 7.5 x 1018, the number of particles in the universe is between 1072 and 1087. Clearly, if there really are more chemicals than this, then not every one even physically exists in the universe. The most abundant compound in the universe, by far, is diatomic hydrogen (H2) anyway. Out of the 117 known elements, only 94 are found naturally, and seven of these are noble gases, which only form compounds under very unusual conditions, such as when exposed to electron bombardment. This leaves 87 more elements to form chemical compounds, and most of these don’t form many, nor are they very abundant. The most abundant elements in the universe are hydrogen (74%), helium (24%), oxygen (10%), carbon (0.46%), neon (0.13%), iron (0.1%), and nitrogen (0.1%). Helium and neon are noble gases and don’t bond with anything. Iron mainly is locked up in iron oxid
CAS has data on 33 million different chemicals. About 3 million chemicals are available and about 30,000 are “common,” i.e., used in commerce. How many chemicals are known to be harmful or benign? The gruesome truth is that less than 1,000 chemicals have adequate toxicity testing. A few thousand more have some testing. Knowledge about the rest is based on guesswork perhaps relating its structure or other properties to data on chemicals with similar structure or properties, about which something is known. Module 3 Index ENVE 649 Homepage.
