Searching the Literature
Bibliographic databases (i.e., indexes) are vital for searching the primary literature, but they are not optimally designed for identifying property data contained within original documents. SciFinder is by far the best index to consult, but others such as Inspec and Engineering Index can be helpful alternatives.
SciFinder (Chemical Abstracts) indexes millions of documents from the late 19th century up to last week that may contain desired physical property information. But you have to understand how to do it correctly, as well as the database's scope, structure, and limitations. For example: If the data in question was the main topic of the article, values may even be shown in the abstract. But if the document just noted the data in passing, the abstract and indexing may give no indication of its presence. The quality and thoroughness of CA's human indexing varied over the years, and was generally less consistent in the decades before 1960. Trying a search several different ways can reduce uncertainty. You can search either by References or by Substances:
Start with the Research Topic query using a property name connected to the substance's Registry Number or common name.
dissociation constant OF 7778-77-0
heat formation AND 10045-86-0
enthalpy vaporization OF alumina
- The OF operator causes SciFinder to look for records that contain both the property name and the RN anywhere in the record. You can choose the references with the concepts "closely associated with one another" to increase precision further. The AND operator just looks for the concepts anywhere in the record but doesn't offer the proximity option.
- If the property index term contains a connector, such as OF in "Heat OF formation," omit the connector from your query.
- SciFinder automatically includes certain synonyms and plurals in your search. For example, heat = enthalpy and both terms will be retrieved by searching one of them.
- Use the RN as a search term in place of a chemical name. Your search will be more precise by avoiding name-fragment hits that are not directly related to the compound you're seeking. However, see the next tip.
- When CAS converted older years of CA to digital format, the Registry Number for a substance was algorithmically assigned to the article record ONLY if the original Subject Index for that period included a reference to the article under the substance's CA Index Name. In some cases, CA abstracters only made this assignment when the substance was the main focus of the document, ignoring other compounds that may have been mentioned. (The conversion project made no attempt to re-analyze or re-index the original literature.) Searching by common name instead of RN occasionally yields some articles where the name appears in the title or abstract but was not specifically indexed for some reason.
Start from the Explore Substances search:
- Search for a substance by Registry Number, molecular formula, name, or structure.
- Click "Get References" and retrieve references from all years.
Selecting "Properties" from the "roles" pop-up menu will retrieve only post-1967 references. (The Properties role has not been retrospectively assigned to RNs before that date.) Since much fundamental property data was reported before that time, you should skip this menu and just get all references.
- Use the Refine tab to limit the results set using a property name.
- A free tool from NIST-TRC that allows you to search precisely for references reporting desired property and substance-level data within the NIST SOURCE Data Archive, and then generate a PDF literature report as required by a number of data-focused journals. The Archive covers reports of pure compounds and binary and ternary mixtures. (Polymers, materials with unspecified formulas, ions, and reaction properties are not included.) Note that the actual data is not provided in ThermoLit; that can often be found in the related Web Thermo Tables database.
- Thermophysical Properties Research Literature Retrieval Guide
- Old-fashioned but totally unique.