SciFinder: Substances

How to use the world's largest chemical information database to find chemical references, compounds, and reactions.


Substances are at the heart of chemistry and of SciFinder.  SciFinder has always placed a priority on identifying substances in the chemical literature.

Information on searching for substances:



Entry Points

SciFinder provides several ways to locate substance records. From this record you can quickly find literature in which the substance appears, often in specific Roles such as Preparation or Analytical Study.

  • Chemical Structure -- Use the drawing window to search for a structure or a substructure
  • Markush Structure -- Use the drawing window to search for more general structures that resemble the claims made in patents
  • Name (under Substance Identifier) -- An excellent way to directly go to a substance record. Usually you only get the substance you want, not isotopes or multicomponent substances. Compare drawing chlorobenzene with using its name in Substance Identifier.
  • CAS Registry Number (under Substance Identifier) -- If you know the CAS Registry Number of a substance, this is quick way to its substance record. Find up to 50 substances at one time using the Substance Identifier.
  • Molecular Formula -- Usually this is least helpful way to find a substance or group of substances, but occasionally it is the best way to search for substances.
  • Links from other parts of SciFinder -- Anytime a link is associated with a substance,  it will take you to the substance record.

Thank You

Content from this page is from Auburn University's SciFinder LibGuide, by Bob Buchanan, who kindly gave us his permission to re-use it. 

Precision Analysis

Precision Analysis

Check the box called "Precision Analysis" when you do substructure searches. This is extremely valuable for inorganic substances substructure searches.

Inorganic Substances

SciFinder has a generous view of what might constitute a bond, especially in inorganic substances. SciFinder substructure searches often imagine a bond between atoms in different components of a multi-component substance (which frequently make little sense chemically). Precision Analysis allows you to restrict the search to "Conventional Structure" which will give you what was drawn in the structure search. Note that you need to check the box for Precision Analysis before starting a structure search.

Why does SciFinder include "Non-conventional Structures" in substructure searches?SciFinder prefers to find "false hits" and have you remove them from an answer set rather than to miss results that might be helpful to you.

Organic Substances

SciFinder substructure searches of organic substances also sometimes find substances in which the a ketone migrates into enol and then into a double bond. Choosing "Conventional Structures" in Precision Analysis will focus on structures that more closely match what was drawn.


Three Ways to Search for Preparations
Explore Reactions Use the reaction drawing window
Explore Substances Choose references for Preparation. This is the best.
Explore References Type in "preparation of [insert the CAS Registry Number]. This is just as good.   

Substance Roles

Since 1966 ... but all years for the Preparation Role.

SciFinder applies Roles to the substances it finds in the chemical literature. This helps researchers find articles in which the substance played a particular "role" such as Preparation, Uses, or Analytical Study.

Limiting a substance to the references in which it plays a particular Role can be a powerful way to focus a search. Preparation, Uses, and Analytical Study are the most useful Roles, but there are other Roles that can be helpful.

  • Substance Roles: Analytical Study; Biological Study; Combinatorial Study; Formation (Nonpreparative); Occurrence; Preparation; Process; Properties; Prophetic in Patents; Reactant or Reagent, and Uses.
  • Roles have been assigned to all substances in SciFinder for literature published since 1966.
  • Prior to 1966, only the Preparation Role has consistently been assigned for all substances. This makes finding literature reference to preparations fairly easy in SciFinder – but not for other Roles that a substance may play.
  • There are a few exceptions to these generalizations – all Roles for all years have assigned for a few major chemicals such as benzene, ethanol, and formaldehyde.

Substance Types

SciFinder places substances in six general categories:

1. Single-Component Substances

  • Inorganic
  • Organic
  • Isotopes
  • Stereoisomers
  • Intermediates

2. Multi-Component Substances

  • Salts
  • Alloys
  • Mixtures
  • Polymers
  • Homo-polymers
  • Co-polymers

3. Metal Complexes 

  • Bonds to metals are often ignored in structure searches.  To get more precise answers, Analyze Substances by Precision.

4. Incompletely Defined Substances

  • Reference lacks sufficient information

5. Minerals

6. Sequences 

  • SciFinder treats sequences differently than substances – even though the distinction is somewhat arbitrary. Most sequences consist of amino acids or nucleic acids.

Refine and Analyze

Use SciFinder's Analyze Tool to learn more about the search results. Use the Refine Tool to limit the search.


Bioactivity indicators

Commercial availability


Reaction availability

Substance role (the default sort)

Target indicators


Chemical structure -- probably the most useful Refine Tool

Isotope containing

Metal containing

Commercial availability

Property availability -- Property data is incomplete and inconsistent

Property value -- Property data is incomplete and inconsistent

Reference availability

Atom attachment -- Neat tool. Click on an atom in the structure to see what elements are attached.

Image source:  Theresa Knott.  Wikimedia Commons.  GNU Free.