Notice about CAS Registry Numbers®

    Results for conversion of either structure -> CAS Registry Numbers® or CAS Registry Numbers® -> structure are retrieved from publicly available sources hosted by the U.S. National Institutes of Health (“NIH”) and the Wikimedia Foundation. The information is transferred using HTTPS connections.

    Configuration of a proxy

    Since these conversions require an internet connection, if might be necessary to configure a proxy in case your environment uses a firewall that blocks it otherwise. This can be done by using the standard Java system properties, such as https.proxyHost and https.proxyPort. The complete list of properties can be found in the Java documentation for proxies.


    For the aforementioned conversions, each structure or CAS Registry Number®will be sent out to public database server to retrieve CAS Registry Number® or structure, respectively. Please do not choose using such conversion optionally offered if any structure is confidential or you do not want to give any particular CAS Registry Number®out of your hands for any reason. You are taking full responsibility and ChemAxon shall assume no liability whatsoever if you proceed further.

    CAS Registry Number® is a registered trademark of the American Chemical Society.

    CAS, a division of the American Chemical Society, is the authoritative source for a CAS Registry Number®. Please contact CAS at for more information about assignment and validation of a CAS Registry Number®.