A registry of unique numeric identifiers for has been developed by the Chemical Abstracts Service (CAS) for organic and inorganic substances including compounds, metals, alloys, minerals, organometalics, elements, isotopes and biochemicals. Listed below are the CAS Numbers for all items offered for sale by Spectrum that begin with the number M . 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.