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A passport to the world of chemistry: Why is the CAS number an essential tool for global science?
In the scientific community, the identification of chemical substances is a vital task. As thousands of chemical compounds are discovered and named, the scientific community needs a unified way to identify and manage these substances. It is in this context that Chemical Abstracts Services (CAS) created the CAS Number, also known as the CAS Registration Number (CAS RN), to ensure that chemical substances can be tracked and queried easily and accurately.
CAS RN is a unique identification number that provides a uniform way to identify each chemical substance.
At latest, the CAS registry has identified more than 204 million unique organic and inorganic substances, and 69 million protein and DNA sequences. This extensive database has been continuously updated since 1957 and around 15,000 new substances are added every day. This not only helps researchers look up information about chemicals, but is also crucial for pharmaceuticals, environmental science and other fields.
History and Use
Before the introduction of CAS numbers, the scientific community often faced the challenge of how to effectively identify chemical substances. Since the same compound may have multiple different names, including synonyms, commercial names and their structure-dependent nomenclature, literature searching can be a challenge. To address this problem, CAS developed an algorithm that converts chemical structures into computer-readable data and makes it the basis of the chemical registration system.
The CAS registration system has been publicly available and provides CAS numbers for chemical substances since 1965. These numbers allow researchers and industry professionals to conduct precise searches in various scientific and industrial fields.
CAS Number Format
A CAS number consists of three parts separated by hyphens. The first part consists of 2 to 7 digits, the second part is 2 digits, and the third part is 1 digit, which serves as a check digit to improve the accuracy of the input. The format is designed to allow CAS to have the potential for up to 1 billion unique numbers. For example, the CAS number for water is 7732-18-5, and the calculation method for its check digit demonstrates its accuracy and reliability.
CAS numbers have no inherent meaning but are assigned sequentially based on the order in which the substances are identified by CAS scientists.
Segmentation and Search
Different stereoisomers and racemic mixtures are assigned different CAS numbers, providing clear identification of chemical complexity. In addition, although the same substance in different states will not have different CAS numbers, different crystal structures will have unique identifiers. This systematic indexing method enables researchers to easily obtain the specific material information they need.
With the advancement of technology, many search engines and databases have begun to support the search function of CAS numbers, such as CHEMINDEX, ChemIDplus and Eastlake Chemical Substance Information System. This makes the research and application of chemical substances more convenient and faster.
Future Outlook
As new chemical discoveries and technologies continue to emerge, CAS will continue to play its role as an important tool in the field of chemistry. In current scientific research, the CAS number is not only an identification code for chemical substances, but also the basis for communication and cooperation among the global academic community. The growing demand for chemical data will prompt CAS to continuously innovate and update to meet the expectations of the scientific community.
In this context, have you ever thought about what challenges and opportunities your knowledge will bring in future chemical research?
