Chemical Abstracts (Printed)

昵称13265139 2013-07-23

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[For Librarians: To discard or not to discard?]

Chemical Abstracts was published in print from 1907 to 2009. The Mallet Chemistry Library has a complete run from 1907 through 2001. Chemical Abstracts is shelved in the center of the library, in reference ranges R1-R5. The Collective Indexes are shelved in ranges R1-R3.

Parts of Print CA

Abstracts
There were 26 weekly issues per semiannual "volume". Each Abstract issue is divided into 80 Subject Sections. An abstract appeared in just one section, based on the novelty of the process or substance being reported in the literature. Each weekly issue also contained indexes by author, subject keyword (not official headings), and patent number. The issue indexes were superseded first by a volume index published every six months, and then by the 5-year Collective Index. (The library did not retain the issue and volume indexes.)

Collective Indexes
Every five years CAS published a Collective Index (CI). The 14th CI was published in 2002 and covers the years 1997-2001. The library has all Collective Indexes up to this point. They are divided into:

Author Index, 1907-
Subject Index 1907-71 (included chemical substance names through 1971)
Chemical Substance Index, 1972- (includes all CA Index Names used during the specific index period)
General Subject Index, 1972- (includes all subject and compound-class terms that are not systematic CA Index Names)
Formula Index, 1920- (no formula indexes were compiled for 1907-19)
Patent Index, 1907-

Index Guides
The Index Guide (IG) for each Collective Index period provides cross-references from commonly used chemical names to official CA Index Names (with registry numbers) used in the corresponding Chemical Substance Index. It also serves as a thesaurus of all controlled-vocabulary subject headings used in the General Subject Index. The Index Guide should always be consulted before looking up a chemical name or subject term in the Collective Indexes.

Ring Systems Handbook
The RSH leads you from a ring or cage structure to the CA Index Name and Registry Number of a ring parent compound, for searching in the Chemical Substance Index. Entries are in ring analysis order and are indexed by molecular formula and Index Name.

Registry Handbook
The Registry Handbook - Number Section was a cumulative numerical listing of all registry numbers assigned to chemical substances from 1965 forward. If you have only a registry number and need the CA Index Name for that compound, look it up here first and then use the name to consult the Chemical Substance Indexes. A corresponding Names Section (available on microfiche) provided registry numbers for several hundred thousand of the most-indexed common names.

CASSI
CASSI (Chemical Abstracts Service Source Index) is the comprehensive and retrospective list of publications that have been indexed by Chemical Abstracts since it began in 1907. It includes journals, books, conferences, and other series, arranged by CA abbreviation. This is the source you use to translate journal title abbreviations into full titles for searching in the library catalog and other finding aids. CASSI is located on the Circulation Desk. It is also available in a somewhat limited form on the web.

* The tools described above are no longer published or updated in print as of 2010.

Using CA

Select an appropriate Index volume based on the type of search you want to do (author, substance, or subject) and the time period desired.
- Author: Entries are arranged by last name, then by first and second initials (not by first name). Qualifying text is the title of the document. Coauthors are cross-referenced to first author.
- Formula: Entries contain only abstract numbers unless there is a large number of them, and no qualifying text. It's best to use the Formula Index to get the corresponding CA Index Name, then look up that name in the corresponding Chemical Substance or Subject (1907-71) index, where the entries are more detailed. Formulas are listed in Hill order.
- Chemical Substance name: Start with the Index Guide to see if there's an entry for the name you have. If not, use the Formula Index or Ring Systems Handbook to get the name. In the CSI you must use only the specific CA Index Name for that CI period. There are no cross references to earlier or generic names. Names are arranged by "parent" (the structural skeleton) followed by substituents and modifications. Qualifying text in each entry indicates what the document is primarily about, followed by an abstract number. About 600 of the most frequently indexed compounds are called "Qualified Substances." Their document entries are grouped into seven categories: Analysis, Biological studies, Occurrence, Preparation, Properties, Reactions, Uses and miscellaneous.
- Subject term: Always check the Index Guide first to find an appropriate term to look up in the Subject Index (1907-71) or General Subject Index (1972- ). Classes of compounds (e.g. Carcinogens), undefined compounds and mixtures (e.g. Gasoline), processes, plant/animal species, and other general topical terms are found in this index, along with cross references and scope notes.
- Patent number: Arranged by issuing country/organization, then by patent number. CA abstracts only the first member of a patent family, and links later equivalent patents to this parent patent. Equivalents are cross-referenced to the parent. Prior to 1981 the equivalents were listed in the Patent Concordance.

Note Abstract Numbers from the entries of interest. Abstract numbers prefixed "R" indicate a review; "P" indicates a patent.

Go to the corresponding Abstracts volume and look up the abstract by its number.

Repeat this process for earlier or later index periods. Remember that Index Names and subject headings changed over time, so consult the Index Guide for each CI period.

The CA Abstract Number Puzzle

The format of the CA Abstract Number has changed over time as CA evolved. Only 1967-forward abstract numbers are searchable as "document identifiers" in SciFinder. "CAN" numbers displayed in SciFinder for pre-1967 records do not correspond to the printed CA abstract number.

Dates	Example	Notes
1967-present	74:23628c	Represents a single specific abstract; searchable in SciFinder. The final control character appears only in the print abstracts and should be ignored.
1947-66	45:1541e	Volume:Column number/column fraction letter a-h. Abstract numbers prior to 1967 do not necessarily represent a specific abstract, but rather the position in a column or page where that abstract begins.
1934-46	28:3714⁵	Volume:Column number/column fraction digit 1-9
1907-33	6:571	Volume:page only.

Is there still a reason to use print CA?

In most cases, no. CA's size and complexity can confuse even the experienced searcher. It's much faster and more convenient to use a database version, such as SciFinder. There are however some occasions when print CA is still useful:

When you need to look up a pre-1967 CA abstract number (e.g. CA 53:2185a), you must use the print version; these numbers are not searchable or displayed in SciFinder. See the SciFinder FAQ for more information. Library staff are happy to provide this service for you - just use the Ask a Question form and provide the exact reference needed.

The highly structured organization of the Chemical Substance Indexes is easier to browse than trying a hit-or-miss chemical structure, name or formula search in SciFinder, especially when searching for salts, esters, and other derivatives of parent compounds, as well as multicomponent substances such as copolymers, alloys, tabular inorganics, and mixtures. In these cases, be sure to start with the Index Guide and/or Ring Systems Handbook to find the proper name entry in the CSI.

Help Using CA

See the CA Tips page. A booklet called "How To Search Printed CA" is available in the library with the CA indexes.

For Librarians: To Discard or Not to Discard, That is the Question...

Should a library discard or remote the last copy of print Chemical Abstracts? Ultimately, the decision must be based on local needs and situations. Here are some points to consider, gathered from collective wisdom of many experts.

SciFinder is not identical to Chemical Abstracts. All (or nearly all) the content of the latter is included in the CAPLUS file and robustly substance-indexed via the Registry file. But it is an oversimplification to say that you can do everything in SciFinder that you could do in the print.

The Collective subject/substance/formula indexes allow browsing of chemical names, formulas, and subject headings in a way that isn't possible in SciFinder. SciFinder is great for snapshots, but it doesn't provide any view of the hierarchical structure of the CA database, or its indexing and nomenclature practices; nor does it allow easy browsing for derivatives, salts, and other variants of a parent structure. In other words, you can't browse online for nearby entries like you can in the print, which removes a serendipity factor. For some purposes, this is an important distinction. (Browsing index entries is possible in STN.)

When you can't figure out how CAS has defined the structure or formula of certain types of compounds, especially inorganic (salts, hydrates, ions, decimals, etc), coordination compounds, and multicomponent substances, SciFinder can be frustrating. Using the Index Guide and Chemical Substance Index can actually save some time, and when you find the Registry number then you can go back to SciFinder, locate the substance record and complete the literature search. (Of course, this method only works for compounds registered before your last Collective Index.)

Pre-1967 CA abstract numbers (see above) are not searchable or displayed in SciFinder, and can only be looked up or verified in the print. These numbers are occasionally cited in the older literature, especially as stand-ins for obscure and foreign documents.

Some printed abstracts may contain structure graphics that aren't duplicated online.

SciFinder is not available to a library's unaffiliated users, per license restrictions.

CA in print is now, of course, only for historical searching. Even if you were to lose access to SciFinder, print CA could not be an acceptable substitute for modern users.

If you have bound any of the six-month volume indexes, and you have the equivalent Collectives and their Index Guides, the former are expendable and should be discarded to save shelf space. And hopefully the weekly issue indexes were sliced out and discarded before binding -- those are indeed useless and add a significant amount of linear footage.

Even if you decide to discard the bulk of CA, consider retaining the most valuable parts, such as the Index Guides (very useful for finding index terms, synonyms, controlled vocabulary, Registry Numbers, etc.). If you wish to split the run by time period, general wisdom suggests that the older (and smaller) pre-1967 portion of CA is more useful archivally than the post-1967 volumes.

Remote storage is a false solution. Indexes stored remotely in closed-stacks facilities will almost certainly never be used again, and can't be used for their intended purpose anyway. So this is essentially no different than discarding them.