UNIT – II

CHEMICAL ABSTRACTS

Current awareness searching: CA weekly issues, CA issue indexes. Retrospective

searching: CA volume indexes - general subject index, chemical substance index -

formula index, index of ring systems, author index, patent index. CA collective

indexes: collective index (CI), decennial index (DI). Access points for searching CA

indexes - Index guide, general subject, terms, chemical substance names, molecular

formulas, ring systems, author names, patent numbers. Locating the reference:

finding the abstract, finding the original document chemical abstract - service source

index.

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CA Weekly Issues

As it sits on the library shelves, looks like a large collection of identical books.

This appearance is deceptive, but, each book of CA has a different purpose and can

play a unique role in help to find the information you need.

There are two ways search the CA: (1) Consult the Weekly Issues for current-

awareness searching or (2) Consult the Volume or Collective Indexes for backward

searching.

Each week, CA carries approximately 10,000 abstracts of the newest findings in

chemistry and chemical engineering reported in scientific and technical literature

worldwide.

Over 9,000 scientific and technical periodicals from more than 150 nations,

patent documents issued by 26 nations and two international bodies, conference and

symposium proceedings, dissertations, government reports and books from around

the world are monitored for new relevant to chemistry or chemical engineering.

These abstracts give brief, informative summaries of the new chemical information

contained original documents.

Abstracts in CA are placed in one of 80 sections based upon the importance of

the documents. The sections are collected into five broad groupings labeled,

Biochemistry (sections 1-20), Organic Chemistry (21-34), Macromolecular Chemistry

(35-46), Applied Chemistry and Chemical engineering (47-64) and Physical,

Inorganic, and Analytical Chernistry (65-80). Sections 1 to 34 are published one

week; sections 35 to 80 are published remaining weeks.

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 Since abstracts are not duplicated in CA, the primary focus of their content

determines the section in which they appear. Cross-references for abstracts are

provided at the end of each section. These cross-references indicate abstracts whose

diverse subject content might have permitted placement in any one of several

sections.

Sequential numbers are assigned to abstracts from the beginning of each six-

month volume period. These numbers are headed by the volume number. Each

abstract is accompanied by a bibliographic heading that completely identifies the

original documents.

CA Issues Indexes

Accompanying the CA weekly collections of abstracts are three indexes, (1) an

index of author’s or inventor’s names, (2) an index of keyword phrases chosen from

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the abstract text and document titles and (3) an index of patent numbers. These

indexes provided you with access points for locating abstracts on your subject of

interest.

In-depth indexes refer to six-month collections of CA abstracts. Subjects

covered in these indexes are selected from the original documents, not just the

abstracts, and the terms used reflect a controlled vocabulary chosen to prevent the

indiscriminate scattering of the index references.

The set of volume indexes includes

 General Subject Index  Index of Ring Systems

 Chemical Substance Index  Author Index

 Formula Index  Patent Index

The chart below shows the date at which each index was introduced and

illustrates two important changes. Before 1972, the General Subject and the Chemical

Substance Indexes were published as a single Subject Index. The Patent Index was

issued in two parts before 1981: the Numerical Patent Index and the Patent

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Concordance. Prior to 1962, volume Indexes were published annually rather than

semi-annually.

Volume and Collective Indexes: General Subject Index

 The General Subject Index uses standard subject headings in order to better

bring related documents together (collation).

 The standard headings list does get modified and expanded to reflect new

areas of research. Major changes are usually done at the beginning of a

Collective Index period. Sometimes the changes are minor, sometimes drastic.

 Prior to 1997, headings were chosen so as to draw related topics into physical

proximity in the printed volumes, with electronic searching treated as a

secondary aspect of CA. Starting in 1997, headings have been changed to be

more like natural language for easier electronic searching, with the print

version treated as a secondary aspect of CA.

 For examples of the 1997 changes see the CAS General Subject Vocabulary

Helper at http://www.cas.org/vocabulary/

 Broadly speaking, the General Subject Index includes:

 classes of chemical substances

 physical and chemical phenomena

 types of reactions

 chemical technology

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  industrial processes and equipment

 scientific names for living organisms

 biological and medical terminology

 For extensive subjects, qualifiers are added as part of the main subject

heading, such as

 Blood, analysis

 Classes of substances may also have derivative categories, such as

 Carboxylic acids, esters

 Sulfonic acids, uses and miscellaneous

 Note: the following lists of categories apply to pre-1997 indexes. Some are

undergoing dramatic changes.

 Substance Categories

 For ketones, aldehydes

- acetals, hydrazones, mercaptals, oximes

 For acids

- anhydrides, anhydrosulfides, esters, lactones

 For alcohols

- ethers

 For amines

- oxides

 General: compounds, derivatives, polymers

 Heading Qualifiers

 For substances and classes of substances

 analysis

 biological studies

 occurrence

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  preparations

 properties

 reactions

 uses and miscellaneous

 In the electronic versions of the file, these have evolved into role

indicators.

 For organs and tissues

 composition

 disease or disorder

 metabolism

 neoplasm

 toxic chemical or physical damage

 In post-1997 subject headings, the disease and neoplasm headings have

been combined with their respective organ or tissue to form separate

primary headings.

 For alloys

 base - applied to the largest single constituent of the alloy.

 non-base - applied to other constituents of the alloy.

Chemical Substance Indexes

The Index Guide provides you with a systematic CA index name for many

common and trade names of chemical substances. The index name identifies a

specific chemical substance and can be scanned in the Chemical Substance Index,

which is ordered alphabetically by index name. Entries in this index also include text

modification phrases, which describe aspects of the substance that were studied.

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Molecular Formula Index

 While most molecular formulas have a large number of possible compounds.

It is far easier to look at a possible name and decide whether it matches your

compound than to guess at a name.

 Note that the Molecular Formula Index just gives a list of abstract numbers,

not a breakdown by subheadings.

Molecular Formula Index Organization

 Molecular formulas are listed in Hill order.

 If carbon is present, it comes first, followed by hydrogen, then all other

elements in alphabetical order.

 If not, then all (including H) in alphabetical order.

 Note that the rules for salts apply to molecular formulas, too.

 Molecular Formula Examples

 Benzene is C6H6

 Teflon is (C2F4)x

 Ferrocene is C10H10Fe

 Hydrochloric acid is ClH

 Benzoic acid is C7H6O2

 Sodium benzoate is C7H6O2, sodium salt…NOT C7H6NaO2

Index of ring systems

 Most compounds with a polycyclic ring system use the name of the ring

system as the parent compound.

 The Handbook lists ring systems in order of:

 Increasing number of rings

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  Increasing number of atoms in the ring

 Increasing Hill order formula of the ring

 Step 1: Count number of rings, using the smallest rings in the structure

which will take in all the atoms in the ring system - 5

 Step 2: Count the number of atoms in each ring - 5, 6, 6, 5, 5

 Step 3: Note the “molecular formula” of each ring - C5, C6, C5O, C4O, C5

 Step 4: Arrange the formulas in order of increasing size and Hill

order: C4O, C5, C5, C5O, C6

 Step 5: Look up the ring systems that fit the formula and pick the

correct one by inspection (not always easy).

 Resulting name: 5H-4a,11a-epoxy-7,9a-methano-1H-cyclopenta[b]

heptalene

 The entry for a given ring system gives structure diagram with CAS locate

numbers, name, Registry Number of the parent ring.

 Rings which are less unsaturated will (for complex rings) have the same

parent name, but with, for example, “decahydro” added.

Author Indexing

 Weekly Issues

 All authors are listed by last name and initials only. The index gives

only the abstract number. Examples:

 Lipshutz B H 151869t

 Little R D 152780u

 Patents have entries for both inventor and assignee; their abstract

numbers have P before the number. Examples:

 Genentech, Inc. P146735s

 Leong S R P 146735s

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  Other types of corporate authors, such as societies and government

agencies, also get author entries

 United States Food and Drug Administration 150996v 150997w

 Volume and Collective Indexes

 First authors get both the abstract number and title of the paper listed

under their names.

 The author name is not necessarily the form used in the article, but

may be a standardized form of the name.

 Other authors are cross-referenced to the first author of the document.

 Examples:

 Ford, Peter Campbell

Quantitative mechanistic studies of the photoreactions of…

148754a

 Lange, Frederick Fouse

See Miller, Kelly T.; Sudre, Olivier ---; Lam, D.C.C.; Sudre, O.

Powder processing and densification of ceramics 144196x

 Even though CA tries to pull all of an author’s works under one name,

it cannot always distinguish authors with the same initials, so it

alphabetizes by last name and initials, even where the full name is

spelled out! Examples:

 Ellis, A.

 Ellis, Arthur Baron

 Ellis, A. D.

 Ellis, Anthony Ewart

 Ellis, Avery K.

 Ellis, Andrew Michael

 Ellis, Albert T.

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  Spelling of Author Names: Be aware of special rules for handling certain

names. Names with “Mc” or umlauted letters or transliteration from non-

Roman alphabets can be tricky. Example:

 Mössbauer is listed as Mossbauer

Patent Indexing

 A chemical abstract only indexes the first version of each patent it receives.

 However, the patent index (arranged by country code and patent number)

gives cross-references from later, equivalent patents, that is, the same

invention by the same inventor, patented in a different national or

international patent office.

 When searching for an equivalent patent, start at the year of issue of the

known patent reference and work forward until you find the equivalent or

run out of indexes.

CA Index Guide

 The Index Guide is the key printed tool for identifying the correct subject

heading for any topic in Chemical Abstracts

 Each Index Guide lists the approved headings in use for its period of

coverage.

 An IG is published at the beginning of each Collective Index period, with

updates every 18 months until the final comes with the Collective Index itself.

 Contents of the Index Guide

 An alphabetical listing of the approved subject headings, with cross-

references to related headings and descriptive notes.

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  Many common terms not used as headings are listed, with See

references to the correct heading.

 Many common and/or trade names for chemical substances are listed,

giving the correct CA systematic name (and Registry Number!)

 There are also appendices on the organization and use of the subject

indexes; how CA indexers select headings; CA chemical nomenclature;

and a hierarchical list of the headings.

For instance, a patent for plasma metalizing of various materials is linked to

such keywords ''plasma”, "metalizing", "fibers" and "polymers".

(Keyword Index)

(Index Guide)

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 (General Subject Index)

These keywords are helpful in identifying relevant abstracts among those each

week. Keywords are also useful because they reflect the terminology chosen by

authors in a variety of specialties and from a number of nations. On the other hand,

keywords lack the precision consistency necessary for a used for retrospective

searching.

In semi-annual Indexes and the Collective Indexes, author terminology is

replaced by a controlled vocabulary that prevents scattering of references over

several terms. For instance, abstracts on the subject of cancer-causing agents might

be found under such keywords as cancer, carcinogen, tumor, malignancy in the issue

indexes. In the General Subject Index, all these references would be linked to the

single term 'Carcinogens’.

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 Author terminology is linked to the subject term employed in the General

Subject Index through the Index Guide. The General Subject Index is the appropriate

volume to consult for all the topics other than specific chemical substance names.

General Subject Indexes

Subject terms referring to reactions, processes and equipment; classes of

substances; plant and animal species should be searched in the General Subject

Index. Most entries include a "text modification" phrase that further describes the

aspect of heading topic that was considered when the document was indexed. You

can use this phrase as an aid for selecting the abstracts most relevant for your

purpose.

Each index entry is linked to an abstract number consisting of one to six digits

followed by an alphabetic character. The small letter at the end is intended for

computer verification only-to ensure that the abstract number has been recorded

properly. The capital letter B, P, or R before the number tells you that the original

document is a book, a patent, a review article, respectively.

CA Collective Indexes

When searching for references to scientific work appearing in CA prior to 1992,

you should consider the following points. Every five years the Volume Indexes are

merged and republished as a single index to all abstracts published during the

period-the Collective Index (Cl). Before 1957, collectives covered 10 years and were

called Decennial Indexes (Dl). The collectives and the CA volumes they include are

further described the chart below. Searching the Collective Indexes instead of the

individual Volume Indexes can save you much time if you are performing a search

covering several years.

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 CA issues have been published weekly since 1967. Before then, all sections

were published together on a biweekly basis. The content, arrangement, number of

sections has also changed over the year.

Prior to 1967, the abstracts were designated in the Volume and Collective

Indexes by a number with a superscript letter. The number represented a column in

CA and the superscript letter represented the fraction of page where the abstract of

interest could be found.

Because the Indexing system of CA is so thorough and comprehensive, each

abstract has a variety of access points. You can find abstracts that can help you in

your writing research by beginning with one or several of the following pieces of

information:

 a genera] subject term

 a chemical substance name

 a molecular formula

 a ring system

 the name of an author, co-author, or inventor

 a patent number

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Chemical Substance Names

Knowing a substance's name, its molecular formula, or the analysis of its

constituent rings can provide you with valuable pointers in your attempt to locate

abstracts describing the substance of interest.

If you have the name of a substance, you can begin your search with the

chemical substance indexes. The weekly CA Issue indexes provide access to

substance-related abstracts through the chemical names used by authors and

invertors. These names are included with subject terms in the weekly Keyword

index at the back of each issue

For instance, if you are interested in abstracts concerning the following

substance,

You would look in the Keyword index under the name "carbapenem."

(Keyword Index)

Although helpful, these entries are not consistent enough to serve as the basis

for a thorough and comprehensive index. For one thing, many substances have more

than one name. The common industrial polymer polyethylene has more than 900

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names on record. In addition, some trade names are little than codes, such as AQ

110, which would be meaningless as an index term.

To maintain consistency in its indexing policies, CAS has extended

nomenclature principles adopted by the International Union of Pure and Applied

Chemistry (IUPAC to develop names in a precise manner ensuring that each

substance receives a single name and that each name completely describes a single

substance. These names, called CA index names, are the basis for classifying

substance information in the Chemical Substance Index.

Index names are built around a “parent”, generally the name of a structural

skeleton plus a suffix denoting the principal group. The index name is inverted so

that the parent appears first in the name printed in the index. This practice allows

substances with the same structural skeleton to appear near each other in the

alphabetically arranged index.

Substituents on the parent structure are listed next in the name. They may be

followed by a “modification” that identifies a specific derivative (such as an ester) of

the principal indexed substance. Stereochemical information, if appropriate, appears

at the end of the name. As an example, the following structure is named

Cyclohexene-carboxylic acid (Parent), 4-chloro-3-(2-(methylamino)ethyl-

(Substituents), methyl ester (Modification), (1α, 3β, 4β) (Stereo)-

If you search frequently for a particular class of substances, it may be

worthwhile to learn the conventions for naming the members of that class. The

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essential rules and procedures for deriving index names are detailed in Appendix IV

of Index Guide.

In most instances, it is not necessary to derive an index name to search for a

substance. If you know a common name, like carbapenem, looking it up in the Index

Guide often will provide the index name. The Index Guide lists about 150,000

common and trade names with their corresponding names and CAS Registry

Numbers. Looking up carbapenem in the Index Guide, for example, would yield

(Index Guide)

(Chemical Substance Index)

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Molecular Formulas

When you know the molecular formula for a substance of interest, you can

consult the Formula Index directly. This volume index provides CA index names,

CAS Registry Numbers, and abstract numbers for chemical substances identified by

molecular formulas.

Element symbols in the molecular formula used in the Formula Index are

arranged according to the Hill system. For all carbon-containing compounds, C is

listed first, followed by H, if present, and then by the remaining element symbols in

alphabetical order. The resulting formulas are ordered in ascending numerical order

in the Index. For instance, CH appears before all substances beginning with CH2,

and all substances containing one carbon atom appear before substances whose

formulas start with C2. Formulas for substances that do not contain carbon are

arranged alphabetically by element symbol. This practice may result in some

formulas that differ from usual chemical conventions. For instance, table salt not be

found under the N's as NaCl, but will appear as ClNa. The following is the Formula

Index entry for carbapenum,

(Formula Index)

While the Formula Index does give abstract numbers for references about most

substances, it does not include the text modifications that describe the content of

each abstract. For this reason it frequently may be more desirable to use Formula

Index to retrieve an index name, and then look up that index name in the Chemical

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Substance Index, where headings are accompanied by text modifications. Entries in

the Formula Index for which a large number of references are published do not

include the abstract numbers, but do provide index names so that you can search

references listed in the Chemical Substance Index.

Ring Systems

You could also begin your search with a ring system, if you know the

configuration of your substance of interest. Each set of Volumes Indexes provides

you with an Index of Ring Systems that orders substances on the basis of an analysis

of constituent ring. An entry is included for each ring system CAS encounters during

a volume or collective period. Performing a ring analysis requires only that three

pieces of information be noted and listed in order: the number of component rings,

the sizes of component rings, and the elemental composition of component rings. For

instance, the ring analysis for ring parent in carbapenem would be

Number of rings = 2

Size of rings = 4, 5

Elemental analysis of rings = C3N-C4N

The Index of Ring Systems is ordered ascending numerical and alphabetical

order of these ring analysis components. Rings that require indicated hydrogen

show the saturated centre in the lowest available position.

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 Each elemental analysis is linked to CA index name for all ring systems that

share the analysis. The index names can then be looked up in Chemical Substance

Index for references about substances containing that ring system.

(Index of Ring Syatems)

A separate, complementary publication, the Ring Systems Handbook, includes

all ring systems encountered by CAS. It contains structure drawings of all ring

systems and cyclic natural products used as parent headings deriving CA index

names. By consulting this publication, you have an alternative route of access to the

Volume Chemical Substance Index.

Author Names

The Issue and Volume Author Indexes link names of authors, Co-authors,

inventors, and assignees to the abstract numbers of documents that they have

produced. Since corporations are frequently listed as assignees of patent rights, these

indexes include corporate as well as personal names.

In the weekly Issue Indexes the author names are listed in an abbreviated form,

consisting of last name and initials only.

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 (Issue Author Index)

Since the number of abstracts in each issue is relatively small, this practice

creates little confusion. In contrast, there may be as many as eight pages in the

Volume Author Index devoted to scientists named Smith, so the fullest available

information is included with each name entry. The order is alphabetical by last

name. Where last names are identical, the order is alphabetical by first initial and

second initial, NOT alphabetical by the letters of first name. Abstract numbers and

document ides are linked only to the first listed author of co-authored papers. Other

author names are cross-referred to the name of first author.

(Volume Author Index)

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Patent Numbers

The General Subject, Chemical Substance, and Author Indexes can lead to

abstracts of patents about particular subjects or substances, or by known inventors or

assignees. Additional routes to patent information are available when the patent

number is known. These are provided by the Patent Indexes, both weekly and

volume, which began publication in January 1981 (Volume 94) (For patents prior to

1981, see tip for searching CA Collective Indexes below).

When looking for a patent number in these indexes, there are two possibilities:

he number in hand may be the first document of patent family encountered CAS

therefore, abstracted in CA; or tie number may belong to an equivalent document.

(The patent family comprises all patent documents that describe the same basic

invention). In the first case, the patent number will be linked to an abstract number

for that document, and a complete history of all equivalent documents will be listed

beneath the entry. In the second, the equivalent will be cross-referred to the patent

number of the first abstracted patent.

(Patent Index)

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Tip for searching CA Collective Indexes

Prior to 1981, patent numbers were indexed in two separate indexes-the

Numerical Patent Index and the Patent Concordance. The Numerical Patent Index

provided abstract numbers for those patents abstracted in CA- the first member of a

patent family to come to the attention of CAS document analysis. Equivalent patent

documents were linked to the abstract of the first family member the Patent

Concordance.

Finding the Abstract

Whether you are conducting a current-awareness search of the CA Weekly

Issues or a retrospective search of the CA Volume Indexes, the object is to locate the

abstract number. You can use the abstract number retrieved from searches of the

various indexes to consult appropriate volume and issue of CA to find the abstract

itself.

CA abstracts are findings-oriented. The abstracts summarize the new chemical

information in journal articles, patents, government reports, dissertations,

conference proceedings, and chapters of books and call attention to the appearance

of books, review articles, articles on the history of chemistry and chemical education,

and biographies of chemists.

(Patent Abstract from CA)

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 The abstract is intended to help you decide whether the original document is

likely to be of interest. Once you have determined that it will be helpful, you can use

the bibliographic heading material as the route to retrieve the document.

(Article Abstract from CA)

Finding the Original Document

CAS provides two services that can help you locate original documents of

interest. One is the Chemical Abstracts Service Source Index (CASS), a reference

publication listing in the libraries that hold publications abstracted in CA. The

libraries are designated by codes that can be looked up to their names and addresses.

CASSI is supplemented quarterly and reissued every five years. By looking up the

abbreviated journal title from the abstract heading, you can find the following,

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 (CASSI)

You can also request a document directly from CAS through the CAS

Document Delivery Service and receive photocopies or loans of most documents

cited in CA since 1978. CAS adheres to all copyright laws. Order forms for the

service can be obtained from the CAS Document Delivery Service, PO Box 3012,

Columbus, Ohio, 43210-0012 U.S.A.

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 (Document)

Chemical Abstracts

Chemical Abstracts (CA) is the well-constructed guide to the chemical

literature of the world, referencing increasingly than 14.8 million documents, since it

was first published in 1907. This completeness ways you can search CA with

confidence, knowing that you won't miss essential chemical information. The answer

to almost any question related to chemistry can be found through CA. CA also

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covers many other related scientific disciplines such as biology, clinical medicine,

physics, geology, engineering and more.

Finding the scientific documents that contain the information you need from

among over 14 million documents might seem like a terrifying task. Searching CA

simplifies the process and offers an efficient ways of finding those documents that

focus on your topic of interest.

Chemical Abstracts provides comprehensive coverage of the world's chemical

literature, and includes biochemistry, organic chemistry, macromolecular chemistry,

applied chemistry and chemical engineering, physical, inorganic and analytical

chemistry.

Chemical Abstracts Consists of Six Indexes

General This semi-annual index covers subject concepts that do not refer
Subject Index to specific chemical substances in the corresponding Chemical
Abstracts. These entries include concepts, general classes of
chemical substances, applications, uses, properties, reactions,
apparatus, processes, and biochemical and biological subjects.
Example Immobilizing proteins on surfaces of yeast cells 165708z
(abstract no.)

Author Index Authors, patentees, and patent assignees are listed in

alphabetical order in this semi-annual index with titles of their
articles or patent specifications and abstract numbers.
Example: Bubner, N.
A mathematical model for deformation-driven experiments on
shape memory alloys, 296185d (abstract number)

Chemical This semi-annual index relates the Chemical Abstracts index

Substance names of chemical substances and their CAS Registry Numbers
Index to Chemical Abstract numbers for documents in which the
substances are mentioned. Included with the Chemical Abstract
name is a brief description of the document's context.

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 Example Phosphatase, glucose 6-[9001-39-2]
in decreased cerebral glucose utilization in ebb
phase of thermal injury, 111823q (abstract number)

Formula Index This semi-annual index relates the molecular formulas for
chemical substances with the Chemical Abstracts chemical
substance index names, CAS Registry Numbers, and
corresponding abstract numbers.
Example C6H1202
Acetic acid
1,1-dimethylethyl ester [540-88-5]
16075a

Patent Index Entries are ordered alphabetically by a two-character code for

the country of issue. Under each country the patent documents
are listed in numerical order. This semi-annual index includes
(1) entries for all newly abstracted documents, (2) cross-
references to the first-abstracted patent and (3) a listing at the
first-abstracted patent of all the equivalent patents.
Example JP01/006065 A2 - Japanese Patent number - JP (Japan)

Index of Ring This index has been discontinued; the last such index appears in
Systems Volume 121, July-December 1994. Ring composition, ring size,
and number of rings are listed providing a means for
determining the systematic Chemical Abstract index names for
specific ring systems as well as the non-systematic Chemical
Abstract index names for cyclic natural products containing
these ring systems. The Index of Ring Systems is found at the
end of the Formula Index.
Example C4S-C5-C6-C6
2H-Cyclopenta [1,2-b] thiophene

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