A brief news item about a terrorist threat in  Britain mentioned Osmium tetroxide.  We had to look this substance up, and the process provided a useful reminder about procedures for looking up a particular chemical in a system like CIS.

Having just a name, we searched for OSMIUM TETROXIDE. The search "worked" -- that is, it retrieved 63 records -- but we bothered to look only at the very first citation in our results list.  This citation-form display was from the SANSS database, and it indicated that the CAS Registry Number for Osmium tetroxide was 20816-12-0.

Having found a CAS RN, we returned to the search screen without even bothering to look at the rest of the results from our first search.  Instead, we re-did the search, this time using the CAS RN instead of the chemical name. The result was much better -- 106 records retrieved by the CAS RN instead of the 63 records retrieved by the chemical name.

MORAL:  When you are searching in CIS and have only a chemical name to go by, look to SANSS to find an appropriate CAS RN for the substance. SANSS contains over 5 million chemical names and synonyms, and your odds of getting a hit in that database for a given chemical name are much greater than in any other CIS database -- many of which contain few or no synonyms. However, it is the CAS Registry Number that you can count on when searching in CIS, since the CAS Registry Number works generally in ALL the substance- oriented databases of CIS.  We have deliberately structured CIS results displays so that SANSS records come up first in any search that hits a  SANSS record -- and one reason for this is to enable you to get the CAS Registry Number for a new search when you only had a chemical name to start with.  If you restrict your searching to chemical names, you're missing a great deal of what the system has to offer.

The TSCAINV database -- TSCA Inventory -- was  recently updated.  This database is ordinarily  updated twice a year, and it's such a matter of  routine that we make little fuss about it.  However, we had occasion to assess the database  statistically this time around, and we thought we  would summarize some of the results for our  users.

For those unfamiliar with it, the TSCAINV  database lists substances included on the public  portion of the "TSCA Inventory," the list  maintained by EPA of chemical substances in industry and commerce in the US.  The appearance of a substance on the list means that it is  approved for use in the United States without any pre-manufacture notice (PMN) to EPA.   A substance  NOT appearing on the list MAY be listed on the  "confidential" portion of the inventory  maintained by EPA -- requiring an inquiry to EPA  to check -- or it may require submission of a  pre-manufacture notice (PMN) to EPA before the  substance can be legally imported or produced.  The version of the database now on CIS -- the first issuance of 2004 -- contains 65,068 substances, and it increases over time:  The first issuance of 2001 had only 64,412 entries, the first issuance of 2002 had 64,645, and the first issuance of 2003 had 64,872.

Each record in the database includes a CAS  Registry Number, and this is the best way to search the database since the records generally contain only a limited number of names/synonyms (see below).  Use SANSS as described above to find a CAS RN if you have only a name.

The limited chemical nomenclature included in each record consists of a formal chemical name -- as defined by the Chemical Abstracts Service in accordance with 9th CI nomenclature rules -- and (possibly) one or more "submitter names" or synonyms -- the name or names used by submitters of substances for inclusion on the Inventory.  If you do search for a chemical name in the TSCAINV database on CIS, a record may be retrieved if it contains your search entry as EITHER a formal chemical name or as a synonym/submitter name. However, only 36,839 of the current 65,068 records contain these alternative names, and most records that have alternative names contain only one or two.  These limitations explain why it's better to retrieve a CAS Registry Number from SANSS by the vast array of synonyms that SANSS contains than to search for a given name in TSCAINV.

A limited number of TSCAINV records -- currently, 2,184 -- may also contain a chemical definition. The chemical definition defines the substance to which the record pertains when the formal chemical name is to some extent ambiguous -- for example, when the name refers broadly to a class of derivatives from a natural source.

A chemical formula field appears in each TSCAINV record, although the field may merely stipulate that all or some portion of the formula is "unspecified." This frequently occurs when the substance in question is of unknown or variable composition, a complex reaction product, or a biological material.  Of the 65,068 molecular formula entries currently in the database, 15,874 include the notation UVCB, denoting "unknown, variable, complex, biological."

TSCAINV records also sometimes include codes indicating the status of the substance with regard to certain regulatory requirements. Currently, 24,942 records (out of 65,068 total) include one or more codes.  Here is a summary of the codes that can appear, with the counts of records in which they appear.