Hello, do you know what happened to the patent chemical abstracts number?

The Chinese full name is "chemical substance registration number", which consists of a set of numbers. Just as we all have our own unique ID cards, each discovered compound has its own unique corresponding number. The appearance of this number can make up for all kinds of troubles caused by inconsistent naming of chemical substances. For example, different countries have different naming methods for the same substance, and many substances have both chemical names and generic names. Therefore, the phenomenon of incomplete data often occurs. Cas only corresponds to one substance, so it is easy to solve this problem. As long as we know the cas number of this substance, we can find the most comprehensive information quickly and conveniently. Let me briefly talk about the composition of cas coding. It consists of six to nine digits. Its general form is # # # aa-aa-a-A. Where # stands for dispensable number and A stands for necessary number. That is to say, the number of digits in front is not necessarily. Some substances are two, up to six. However, no matter what compound it is, it must have at least five digits. In principle, the size of a number can reflect the time when a substance was discovered. The bigger the number, the later it is discovered. At present, more than 20 million substances have their own CAS numbers.