On 10/03/2008, Oldak Quill oldakquill@gmail.com wrote:
There also seems to be a free look-up independent of ACS (http://webbook.nist.gov/chemistry/cas-ser.html). That said, this page is footed with "CAS registry numbers are copyrighted by the American Chemical Society. Redistribution rights for CAS registry numbers are reserved by the American Chemical Society. "CAS registry" is a registered trademark of the American Chemical society.".
"Redistribution rights" is probably the key phrase here - without explicitly saying so, that seems to be the same sort of restriction as SciFinder places on the user. It just makes the lookup process no-charge...