The Chemical Abstracts Service (CAS) has developed a registry of unique numeric identifiers, The CAS Numbers or CAS Registry Numbers , for more than 73 million organic and inorganic substances including compounds, metals, alloys, minerals, organometalics, elements, isotopes and biochemicals. Each number represents only one substance and has no chemical significance but serves solely as an internationally observed substance identifier by scientists, industry and regulatory organizations. A CAS Registry Number contains up to 10 digits, divided by hyphens into three parts with right most digit a check digit. Shown below are fifty (50) of the most popular CAS numbers contained within the Spectrum Chemical product offering along with the CAS number’s chemical name. By clicking on the either the CAS Number or Chemical Name you will be taken to a page which displays all products that have that unique chemical substance. You may also search by CAS number using the numerical 1 -9 links or by using alphabetical listings A – Z links.