Review and Comparison of the Search Effectiveness and User Interface of Three Major Online Chemical Databases
Science Library, University of Florida, Gainesville, Florida 32611, United States
chemical databases are the largest source of chemical information and,
therefore, the main resource for retrieving results from published
journals, books, patents, conference abstracts, and other relevant
sources. Various commercial, as well as free, chemical databases are
available. SciFinder, Reaxys, and Web of Science are three major
chemical databases that contain extensive search options. Herein, we
review these three databases for their search effectiveness and
interface. This comparison will be useful to the undergraduates,
graduates, nonchemistry majors, researchers, and new librarians.
is commonly referred to as the central science, and is used by many
other scientific disciplines. If you ask someone working in the sciences
how often they use chemical information, the answer is going to be very
often. The search for chemical information using different databases is
complicated and time-consuming; it would be nice to know prior to
searching, which database might provide the most informative and
relevant results for a specific query.
chemistry searches, commercial databases such as SciFinder, Reaxys, and
Web of Science (WoS) and free sources such as PubChem and ChemSpider are
available on the web. There are also resources available for keeping
track of recent updates on chemical information sources.(1)
Numerous articles have previously described the coverage and features
for SciFinder, Reaxys, and WoS separately, but none of them have
reviewed and compared them head-to-head after major redesigns in their
respective interfaces and functionality in recent years.(2-9)
In this article, we will provide a brief overview of the three major
commercial chemistry databases: SciFinder, Reaxys, and WoS, and compare
their search methods available, options for refining search results,
technical specifications, and citation export features.
A scientific database collects and organizes scientific information
from research papers, review articles, conference proceedings, and case
reports published in professional journals, patents, and materials in
other platforms and delivers the information about the topic, author,
abstract, publication name and type, and references.(10)
There are various types of databases: citation or bibliographic
databases and full-text databases, as well as databases that contain
chemical structures, chemical reactions, and chemical and physical
Bibliographic databases provide detailed information depending on the
subject and scope of the information and are often linked to other
databases as well as to the primary source. A full-text database is a
compilation of documents or other information available for online
viewing, printing, or downloading. In addition to the text documents in a
full-text database, images are often included, such as graphs, maps,
photos, and diagrams which are often searchable by keywords, phrases, or
databases can be considered search-specific due to how they vary in
content and thus in the various ways they need to be able to search
different information such as structures, reaction schemes, and
synthetic routes. Different types of chemical databases are available:
(1) Bibliographic databases for searching authors, subjects, citations,
or full-text; (2) Numeric databases for searching factual or property
information; and (3) Structure databases for searching molecules or
reactions. Some databases such as SciFinder and Reaxys can be searched
using bibliographic, numeric, and structure searching information.
SciFinder (Chemical Abstract Services (CAS), American Chemical Society)
Academic subscriptions to SciFinder are available by individual login
through the institutional IP Authentication. To use SciFinder, the
first-time user must register with an institutional e-mail account. Once
the registration is confirmed by CAS, the user can use the login and
password. SciFinder has a user-friendly interface and provides many
methods to analyze, refine, or narrow down the search results. In
SciFinder, excerpted data includes experimental, derived, predicted, and
searching SciFinder are available from the main page “Explore
Reference”, “Explore Substance”, and “Explore Reaction”, “Explore
Reference” provides seven additional search options: research topic,
author name, company name, document identifier, journal, patent, and
tags (Figure 1).
by “Research Topic” is a versatile search option and allows for
searches by topic or keyword (name reaction). When searching a phrase or
keyword, SciFinder retrieves the results exactly as entered in the
search box, and/or any closely associated terms and concepts, and/or
containing any one or more of the search words or anywhere in the
reference. Closely associated terms indicate that the terms may be
present in the concept, in the title, in the same sentence, in the
abstract, or in a single Index Heading and its text-modifying phrase,
while “anywhere in the reference” means that the terms are present
somewhere in the title, abstract, and index fields. As such, a user may
retrieve more than one search set. To help filter these sets, the search
results display the “Analyze,”, “Refine”, and “Categorize” tabs. The
“Analyze” tab analyzes the references in-depth by author’s name, CAS
no., company/organization name, document type, index term, concept
heading, journal name, language, and publication year. The “Refine” tab
limits the results by the year, document type, language, and
author/company name. The “Categorize” tab provides more detailed
analysis based on CAS indexing. The “Sort by” menu allows users to
arrange the search results by the publication year, title, accession
number, or number of citations. Once an article is retrieved, related
citation information about the article, such as times cited and cited
references, can be viewed by clicking on “Get Related Citations”. The
substances and reactions in the retrieved references can be accessed by
clicking on the symbols of molecules and green flask icon. The “Quick
View” link provides an image of the abstract; the full text can be
accessed using other sources tab, just below the retrieved record’s
“author name” in order to find variant and alternate spellings of any
given author’s name. The retrieved search results can be selected and
combined to obtain the information indexed under the various
configurations of an author’s name (Figure 2). The retrieved results can further be refined by the company/organization name.
“Substances Search” tab can be used to search for a chemical structure
(exact structure/substructure/similarity), a Markush structure
(substructure or with variables), a molecular formula, a substance
property (boiling point/density/electric resistance/electric
conductance/glass transition temperature/melting point), or a substance
identifier (e.g., chemical name, CAS Registry Number). If the searched
structure has any chiral centers, more than one set is retrieved based
on the similarity to the searched structure. Data sets are generally
classified according to the similarity score of the searched structure (Figure 3).
retrieved results can be arranged by CAS Registry Number, molecular
formula, molecular weight, commercial sources, and similarity score or
number of references. If the compound is commercially available, a link
to the vendor’s Web site is provided. If synthetic reactions are
available, there is a link to the reference reaction. The CAS Registry
Number, molecular formula, and the chemical name appear with the
structure, as well as the similarity score (Figure 4).
a structure or reaction search, SciFinder provides Java-dependent and
non-Java chemical structure editors. As a result of CAS’s collaboration
with the Cambridge software, a user can also launch a structure search
directly from the ChemBio Draw Ultra 2014 or ChemDraw Professional
software. In reaction searches, the “Retrieved reference” option
displays information about the publication referenced, the
reactants/steps/stages, the reaction conditions, and a link to the full
text (Figure 5).
commercial availability of the reactants/reagents and products is made
known to users through the use of an orange flask icon that links out to
the companies selling the reactants/reagents in question. The details
of the reaction or any existent links to similar reactions are readily
accessible via a link to the full text. “Experimental procedure” section
provides the details of the experiment (Figure 5).
addition to the search features outlined above, SciFinder offers the
whole suite of diverse and custom search tools to aid researchers, such
as SciFinder mobile and KMP (keep me posted) alert notification for
relevant topics. Other features include the ability to save search
queries and search results for a current session. SciPlanner is a
function that allows users to plan reactions or syntheses and organize
references. Users can also create and save the projects which can be
printed or shared with other SciFinder users. SciFinder scope includes
searches of single and multiple step reactions. Results can be analyzed
and refined, and can also be grouped by transformation or by the
document. Recently, PatentPak functionality was made available to users
as a one-click patent retriever.(13)
SciFinder is the only one of the three databases discussed here that
allow users to export cited references in a tagged format for importing
into a citation manager tool (CMT). Export of citations to various CMTs
is handled differently, depending on the CMT.(14)
Users need to use .ris for a desktop reference manager and .txt for a
web-based manager. More information can be found using SciFinder’s
online tutorials at http://www.cas.org/training/scifinder.(15)
Reaxys (Reed Elsevier)
Reaxys can be accessed by subscription via institutional IP
authentication as an anonymous user. Although no login is necessary,
users may create their own profile and customize their account settings.
Reaxys interface is very straightforward and self-explanatory. “Ask
Reaxys” is a search box (similar to Google search) where the keywords,
concept, or author can be searched (Figure 6).
can be substances (substance name/molecular formula/CAS Registry no.)
or substance properties (melting point/solubility/ferroelectricity).
“Concept” searches may include reactions (synthesis/reaction type/named
reaction), and “author” can be searched by citation
(author/topic/article). Some records do not have CAS Registry Numbers.
Reaxys can be searched by the reaction, substance,
structure/substructure, and literature. “Literature” can be searched for
the title, abstract, and indexing terms, as well as authors’ names,
patent assignees, publication title, year, volume, and page number (Figure 7).
“Reaxys tree” is a unique feature of the database, and covers the
information about chemical transformation, physicochemical analysis
methods, and quantum chemical calculation methods (Figure 8).
Moreover, it can be searched for the physical properties and spectra
(NMR, IR, MS, UV–visible, and PR), as well as for isolated natural
challenge is conducting a “topic search” using multiple words or
phrases. For example, if the user searches “gold nanoparticles in
nanomedicine”, the results do not include the phrase, but only include
the individual words or combination of words (i.e., gold nanoparticles
and/or nanomedicine) (Figure 9).
“Open Analysis View” provides the histogram analysis of authors,
publications, years, or properties, and can be sorted by count or value.
The analysis window is available for all the retrieved searches (Figure 10).
structure or reaction searches, Reaxys provides built in MarvinSketch
(ChemAxon), a java-dependent drawing editor, and also supports various
other structure editors such as ChemDraw or importing the drawing file
from the desktop (Figure 11).
Reaxys offers the option to generate a structure template from a
chemical name. The retrieved structure results provide the name, Reaxys
Registry number, CAS Registry number, and structure formula, as well as
molecular formula, molecular weight, and InChI key.(16) This also provides active links to the synthesis, details, and original references, as well as the available data information (Figure 11).
In Reaxys, all excerpted data are experimental data, not derived,
predicted, or calculated data. More in-depth information for learning
how to use Reaxys is available in online tutorials at https://www.elsevier.com/solutions/reaxys/learn-and-support.(17)
Web of Science (Thomson Reuters)
of Science can be accessed by subscription via institutional IP
authentication as an anonymous user. Although no login is necessary,
users may create their own account and customize their account settings
to use other features available. The “basic search” initially offers one
search box with the option of adding more search boxes (Figure 12).
The new WoS platform provides access to full text through Google
Scholar. The user can search individually or through a combination of
topic, title, author, groups of authors or author ID, editor,
conference, language, journal title, digital object identifier (DOI),
year published, organization, address, document type, funding agency
(for newer citations), grant number (for newer citations), accession
number, and PubMed ID. On the search screen, users can also search by a
range of years, and select or deselect the Social Science Index and/or
Arts & Humanities Index. If the institution does not subscribe to a
particular index or database, the option for search will not be visible.
One feature that is new with the revamping of the Web site is
lemmatization, where the search algorithm includes spelling variations
(e.g., behavior vs behaviour; tooth vs teeth; fish vs fishes). On the
main search screen, the user may also access all the Thomson Reuter
products the institution subscribes to, such as EndNote Basic, which is
free with a subscription. The main screen also informs the patron of the
collection they are searching, and the type of search (basic, author,
cited reference, or advanced) (Figure 12).
Core Collection offers a wealth of chemical literature in various
scientific disciplines like agriculture, medicine, and water resources.
If the institution only subscribes to the WoS, Science Citation Index
but not the chemical indexes, the user will only find chemical
literature. When searching for a topic, the retrieved results contain
information about the search topic and context. On the left side of the
search screen, the patron will view the search strategy, the ability to
“create an alert” on the topic or author, and to refine results by
various categories such as the subjects identified by WoS, research
areas, author(s), year, document type, and publication type.
reference search is a unique feature of WoS. Through a cited reference
search, a user can discover how a known idea has been confirmed,
applied, improved, extended or corrected. Users can view the H-Index and
Create a Citation Report. Citation reports include yearly analysis of
items and citations (Figure 13)
addition to the search features discussed above, WoS offers other
diverse and custom search tools to help users, such as Marked List,
Search History, and Researchers ID. In search history, saved searches
can be combined or edited. InCites and Essential Science Indicators are
also part of the Web of Science interface and provide analysis of
top/hot/highly cited papers by the research field, author, institution,
journals, countries and research fronts stating cites per paper. More
in-depth information on WoS searching is available through online
tutorials at http://wokinfo.com/training_support/training/web-of-science/.(18)
Web of Science Core Collection: Current Chemical Reactions (CCR) and Index Chemicus (IC)
gain access to the structure drawings, an institution must subscribe to
both “Current Chemical Reactions” and “Index Chemicus”. These indexes
are not standalone databases, but a part of the WoS Core Collection and,
nonetheless, need a special subscription. Current Chemical Reactions
offer over 1 million reactions dated to 1986, and the INPI (Institut
National de la Propriete Industrielle) archive from 1840–1985. More than
1,083,758 reactions are available in 598,871 reaction flows that
include reaction diagrams, critical conditions, bibliographic data, and
author abstracts (Figure 14).
Chemical Reactions” contains synthetic methods reported in over 100
chemistry journals. Index Chemicus provides access to more than 2.6
million compounds dated from 1993 to present and covers over 100
chemistry journals. Users can search Index Chemicus using both text,
structure, and substructure. Other features include full bibliographic
information, graphical summaries, and reaction diagrams (Figure 15).
appears under the article title. By clicking on the individual record
at the bottom of the page, the user will find the structure and/or
compound. To open the diagrams, the user will be prompted to open the
Accelrys JDraw application. Figure 16
shows an example of structures rendered in the program. Unfortunately,
this program only runs on selected version of Java and a computer
operating system that offers a 32-bit processor. Users should be aware
that hardware compatibility issues that might prevent certain desktop
configurations from running the JDraw software.
Comparison of Scifinder, Reaxys, and Web of Science
authors compared the search features, the scope of coverage, subject
and sources, reference age, strengths, and weaknesses in the chemical
databases: SciFinder, Reaxys, and WoS. The results are shown in Table 1.
All three databases offer extensive literature searches with their own
uniqueness. SciFinder and Reaxys are chemistry-centric because of their
structure drawing function and provide a healthy collection of
literature ranging from books to patents, going back to the 1800s and
1700s, respectively. WoS is a multidisciplinary database for literature
searches, and also provides exclusive citation analysis options.
|Comparison Results by Database|
|Features Comparison||SciFinder||Reaxys||Web of Science|
|Provider (Start Date of the Database Interface)||Chemical Abstract Services (1997)||Elsevier (2009)||Thomson Reuters (1997)|
|Ease of Access||Individual login after registration on approved IP address||Accessed through approved IP address||Accessed through approved IP address|
|Common Search Features||Research|
topic, author, substance, reaction, properties, company name,
literature, document identifier, journal, patent, tags, publication year
|Keyword, author, substance, properties, reaction, literature, journal, patent, spectra||Basic,|
advanced, citation, topic, title, author, editor, group author,
publication name and year, conference, funding agency, grant number,
|Scope of Coverage: Sources||Journals, book chapters, patents, conference proceedings, reports, meeting abstracts, chemical catalogs, dissertations||Journals, books, patents, conference proceedings, and abstracts, Scopus and Science Direct||Journals, book chapters, editorials, conference proceedings, book reviews|
|Scope of Coverage: Date Range||Early 1800s–present||1771–present||1900s–present (varies by file)|
|Scope of Coverage: Subject||Chemistry, and life sciences||Chemistry, Medicinal Chemistry||Multidisciplinary|
|Strengths/Unique Search Features||User-friendly|
interface, one-click patent search (on subscription), easy result
refinement, alternate author search with organization affiliation, Java,
and non-Java structure editor
interface, Reaxys tree, quantum chemical calculation methods, Java
structure editor, searching by the large number of properties available
exceptional citation analysis tools (h-index), easy citation export,
citation map linking to the researchers ID, enhanced organizational
field, cited reference search
|Weaknesses||Restricted access that requires individual login, unintuitive citation export to citation management tools||No|
organization searches option with author search, limited citation
export options, limited number of journals covered for deep indexing
|Difficult to use structure drawing editor due to system requirement|
|Citation Export||Up to 100 references can be exported at once||Up to 5000 references can be exported at once||Up to 500 citations can be exported at once (using marked list)|
For example, the reference “European Journal of Medicinal Chemistry
(2002), 37(10), 835–843” was searched, and the citations were compared.
SciFinder showed 90 citations for this article, whereas Reaxys and WoS
showed fewer citations, 74 and 65, respectively. Conversely, the
reference “Chemical Reviews (2009), 109(5), 1900–1947” showed a similar
number of citations using all the three databases. In this case, a
comparison of the given citations in all the three databases indicates
that no database alone would be sufficient to generate an accurate
picture of the available citation information for a given article. As
each database gave a list of incomplete results, none of them can be
said to be authoritative and complete. An additional note on these
results: in looking at the number of citing references, the Reaxys data
is mostly coming from Scopus.
one search “gold nanoparticles and nanomedicine”, SciFinder retrieved 7
references containing “gold nanoparticles and nanomedicine” as entered,
whereas 503 references had two concepts “gold nanoparticles” and
“nanomedicine” closely associated. Reaxys showed no results for this
search, but a separate search for “gold nanoparticles” or “nanomedicine”
resulted in 43,177 citations and 6635 citations, respectively. WoS
retrieved 583 articles when searching “gold nanoparticles” AND
“nanomedicine” as a topic using the Core Collection, excluding the two
chemical indexes. When searching the WoS Core Collection with only the
two chemical databases, CCR, and IC, only two results were obtained for
“gold nanoparticles” AND “nanomedicine”, and with “gold nanoparticles”,
874 records were obtained. As evident from Table 2,
a significant difference was observed in the search results using
SciFinder, Reaxys, and WoS Core Collection, probably because of
different search algorithms. Reaxys and WOS use Boolean operators
including proximity operators, whereas SciFinder uses sentences without
operators. SciFinder uses some unpublished algorithms that work
|Number of Search Results|
|Research Topic||SciFinder||Reaxys||Web of Science|
|Gold nanoparticles and nanomedicine||7a (503)b||0||583|
|Nanomedicine and gold nanoparticles||4a (503)b||0||583|
of the authors was searched as “Christuo, George”. SciFinder retrieved
results with alternate first and last names and provided different sets
of results (Figure 18).
A total of 579 results were retrieved for “Christou, George,” whereas
“Christuo, G” or just “Christuo” had 205 and 4 hits, respectively. These
579 references were further analyzed by the organization name (e.g.,
University of Florida) (203). It is important to mix and match the
author’s first name/initial and last name to get better results in
SciFinder. In Reaxys, the search was conducted using “published by
Author’s name” and retrieved 449 citations for “Christou, George”, but
did not provide the options for alternate spellings or analysis by
company/organization name. WoS provided 203 hits for “Christou, George”,
and the organization enhanced option reduced the search results to 185.
The organizational analysis option is particularly helpful when the
author worked at more than one place, describing what was published from
does not offer this function as a part of Core Collection, but
additional databases CCR and IC can be accessed for chemical structure
search. Given the technical limitations, only SciFinder and Reaxys were
compared. For reference comparison, the chemical name of the compound
“deferitrin” was searched as a topic in WoS, Reaxys, and SciFinder and
retrieved 13, 4, and 26 citations, respectively. We searched for the
substance “deferitrin” by CAS registry no. 239101-33-8, chemical name,
or molecular formula. Deferitrin retrieved 1 result in SciFinder and 4
in Reaxys, whereas the search by CAS no. provided one hit each in
SciFinder and Reaxys (Table 3).
4-Hydroxydesazadesferrithiocin, which is a synonym of Deferitrin,
appeared in references, but did not appear in the SciFinder search when
searching by substance identifier. This may lead to incomplete search
|Number of Search Results|
|CAS no. 239101-33–8||1||1|
Export of citations to various citation management tools (CMTs) is
dependent on the CMT, usually requiring users to export cited references
in a format compatible with the citation manager of choice. To import
into RefWorks or EndNote, the references are first saved in a file and
then imported to the respective programs (Figure 19). It can be difficult to know which export file type to use if the user is not already familiar with the process.
offers multiple citation export options but contains only one
literature management tool option. The export screen appears when
exporting substance results, but the management tool option is not
available during this process. The primary export function page shows
the steps to export citations to endnote after selecting the literature
management system feature (Figure 20).
Ideally, the direct export to Mendeley should be a standard feature
because it is also owned by Elsevier, but that is not an option yet.
offers an easy export option to some of the major CMTs. Because Thomson
Reuters developed EndNote Basic and EndNote Desktop, these two CMTs are
listed as the primary and secondary options, followed by other tools
(i.e., RefWorks). When searching the WoS, you cannot export selected
citations displayed on multiple pages. Instead, you must select
citations or all citations on each page and then add them to the marked
list before exporting them. (You can increase the number of citations
displayed on each page from 10 to 50 by changing the preference at the
bottom of a search results page.) The citations may be exported from the
page displaying the search results or in the individual record (Figure 21).
considering the question: Which database should be used?, the answer
depends on the user and desired information. If a nonchemistry major is
searching the ecological factors of water chemistry in swamps, the WoS
is a great tool. If a researcher is searching the structure of a
chemical compound for medicinal chemistry, then either SciFinder or
Reaxys can be used. In some cases, all the three major databases may be
required, or in other cases, a simple literature search is sufficient.
Reaxys, and WoS offer wide-ranging literature in the chemical sciences.
All the three databases offer unique graphical user interfaces,
features, and functionalities. Each database offers its own version of
search strategies, and the relevancy of the retrieved results vary
significantly. It is important for the user to understand that the
search results retrieved differ depending on the database.
SciFinder is user-friendly, and the drawing editor is intuitive and
easy-to-use. This database is recommended for users with a chemistry
background as well as novice users. Reaxys is also user-friendly,
especially for novice or nonchemistry users with the “Ask Reaxys” search
feature. SciFinder topic searching is much easier to use than Ask
Reaxys. The Reaxys tree is very valuable in providing the reaction
methods, physicochemical properties of compounds, and quantum chemical
calculation tools. SciFinder has indexed single-step and multiple-step
reactions for many years, whereas Reaxys mostly contains single-step and
some “half-step” reactions (products only).
is an excellent overall database and can be easily searched by all
users with great citation management feature. Cited/Citing references go
back to 1900 in WoS; so in order to find information on older
citations, users should definitely use WoS. Subject Categories in WoS
are at Journal title level, whereas categories in SciFinder are done at
the article level. There are no broad subject categories in Reaxys (but
Reaxys through Scopus data does have broad categories). We tried few
additional searches on the topic, author, and substance, but the trend
was mostly consistent throughout. The user, with the help of a professor
or librarian, should consider the use of the desired information and
the educational level and experience before selecting a database. The
online tutorials offer a great way to learn basic searching skills. The
three commercial chemical databases described here provide extensive
chemical information, and users should consult one or all the databases
for any chemistry-related research.
authors would like to acknowledge all reviewers for their constructive
comments and Jose Baca for editorial assistance. Images in the graphical
abstract from SciFinder (a division of the American Chemical Society),
Reaxys (a registered trademark of Reed Elsevier Properties SA), and Web
of Science (a Thomson Reuters product) are all used with permission.
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Review and Comparison of the Search Effectiveness and User Interface of Three Major Online Chemical Databases - Journal of Chemical Education (ACS Publications)