Vol. 24, No. 2
Data in the Age of Computerized Chemistry: Why, How, and When?
John Rumble Jr., Angela Y. Lee, Dorothy Blakeslee, and Shari Young
Solubility Data Series (SDS), begun in the mid-1970s,
is an exhaustive compilation and critical evaluation of all the world's
published results of experimental determinations of solubility. Since
1979, over 70 SDS volumes have been published, including evaluated
data on the solubility of gases in liquids, liquids in liquids, and
solids in liquids. These volumes represent one of the largest collections
of chemical property data ever produced and are the result of work of
scientists throughout the world. Since 1998, and following an agreement
with the National Institute of Standards and Technology (NIST), the
SDS compilations have been published four times a year in the
Journal of Physical and Chemical Reference Data. Since January
2002, a Subcommittee on Solubility and Equilibrium Data of the IUPAC
Analytical Chemistry Division has continued the coordination of the
IUPAC has worked to maintain high scientific standards and a uniform
approach for data compilation and evaluation throughout its existence,
the evolution of personal computing and the rise of the Internet have
substantially changed the ways that research is conducted and results
are made available. In 1980, most communication between compilers, evaluators,
and editors occurred through the mail, and most critically evaluated
research data were published commercially in printed volumes. Only a
few hundred librariesvirtually all in developed countriesmaintained
standing orders for the SDS. Today, collaboration is primarily
via electronic means, with drafts passed around the world as email attachments.
Again with the help of NIST, and as described in this article, the computerization
of the entire collection is being considered as a Web-accessible database.
> Data Evaluation and Reliability
> The NIST Data Programs
> NIST and IUPAC Solubility Data
aspect of chemistry is being affected by the growth of chemical informatics
and the Internet/Web explosion. The once tedious task of building databases
and disseminating them widely has become much easier. Today, some data
gateways point to hundreds of Web sites that provide some type of chemical
information. The accessibility of these data is part of a larger effort
both to improve the quality of scientific data and to make them as widely
available as possible. Before examining the details of computerizing
IUPAC solubility data, it is useful to examine some of the broader aspects
of scientific data.
computers are profoundly changing the nature of 21st century chemistry
research. Already, industrial development and innovation flow primarily
from computer-aided design, model-based processing and manufacturing,
and virtual testing. The confluence of increased computer power, advances
in applied mathematics, and a new generation of highly computer-proficient
scientists and engineers makes the move to model-based research inevitable.
Evaluation and Reliability
regardless of the discipline, has one common feature: Reliable
data are an essential element. Model-based science and engineering cannot
function properly without a large data collection of known quality.
The expression "garbage in, garbage out" applies in every instance.
The generation and dissemination of reliable data is a complex process.
Most scientific and technical data are generated in the course of research
not specifically focused on data measurement and quality. In fact, most
data are scattered throughout the technical literature and are poorly
documented. Data users are not usually experts in how data were generated.
Consequently, even if they find needed data, they cannot easily determine
the quality of those data.
organizations collect and evaluate data so that researchers and others
may use measurement results more confidently. The process of critically
evaluating data involves four key steps:
the data from the published literature;
and evaluating data by experts;
databases and publications to meet user needs; and
those data collections widely.
of scientific data proceeds from three viewpoints. First, the data are
evaluated with respect to how well their generation is documented. Have
all independent variables affecting the measurement been identified?
Have they all been controlled during the measurement?
have these facts been demonstrated and documented? The second viewpoint
is how do the data follow the known laws of nature. The third viewpoint
is how do the data compare with other measurements that purport to look
at the same phenomena.
of these viewpoints depends on the maturity of the discipline and the
existence of previous data evaluation efforts. In areas such as chemical
thermodynamics and atomic spectroscopy, in which knowledge of the measurement
technology is quite developed, the independent variables understood,
and previous evaluations exist, the emphasis in new evaluations is on
the latter two viewpoints. In areas in which measurements are fairly
new, or the phenomena are quite complex and not totally understood,
the emphasis must be on the first viewpoint.
NIST Data Programs
long been interested in data evaluation. Beginning with the International
Critical Tables1 in the 1920s, the National Bureau
of Standards, which was renamed as the National Institute of Standards
and Technology in 1987, operated a large number of data evaluation activities.2
Why is NIST interested in data evaluation? As the U.S. national laboratory
concerned with advancing measurement science and technology, NIST considers
data to be a fundamental result of measurements, both experimental and
calculational. Data collections summarize previous measurement experience,
and data evaluation therefore assesses the quality of current measurement
unique, broad expertise in measurement technology, and the knowledge
and experience necessary to perform data evaluation. NIST measurement
experts are neutral (i.e., they do not favor any particular method except
on merit). Data projects often involve partnerships on a national and
international scale, and NIST has much experience in such partnerships
in terms of sharing responsibility, costs, and outputs.
NIST operates the Standard Reference Data Program, a network of data
centers and projects covering about 40 scientific and technical disciplines.
NIST operates 15 online data systems, available at no charge over the
Web.3 It also sells about 45 individual use databases,
usually installable on PCs.
years, NIST and the American Institute of Physics (AIP) have published
the Journal of Physical and Chemical Reference Data. NIST and
AIP are now committed to creating an electronic journal and, since 1
January 2000, an online, full-text version of the Journal has been available
to subscribers. NIST is building a complementary database, which will
contain important data from the tables and graphs of various articles.
Eventually, we anticipate that the printed and online full-text version
of the Journal will be greatly reduced in size, and the majority
of data will be available through the Journal database.
and IUPAC Solubility Data
NIST and IUPAC signed an agreement to publish four volumes per year
of the IUPAC SDS in the Journal of Physical and Chemical Reference
Data. NIST is providing some help with respect to manuscript preparation,
but the bulk of the work is still performed by the individual volume
editors with funding raised from their own sources.
explosion of Web-based chemical information resources, IUPAC and NIST
began discussions about how best to make the contents of the entire
SDS available online. In 1999, NIST and IUPAC concluded an agreement
to achieve this. Over the next five years, it is hoped that all data
still valid will be made available via the Web at no charge. The remainder
of this paper discusses these plans and the planned system. Because
over 70 printed volumes have been printed, many of which are not available
in computerized formats of any type, a subset has been selected to determine
the best approach to important issues. The first subset deals with the
solubility of halogenated hydrocarbons in water and covers four volumes:
SDS 20 "Halogenated benzenes, toluenes and phenols with water" (1985),
SDS 60 "Halogenated methanes with water" (1995), SDS 67 "Halogenated
ethanes and ethenes in water" (1999), and SDS 68 "Halogenated aliphatic
compounds C3 - C14 with water" (1999).
the NIST-IUPAC solubility data systems involves many activities, including
entry (for volumes not computerized)
uniformity, including translation from old formats
verification, that the numbers are entered or translated correctly
the next few years, these issues will be explored using the subset of
four volumes identified above as a test bed. A prototype database design
has already been developed and data entry is proceeding for Vol. 20.
While NIST is performing this work, IUPAC keeps playing an important
role in giving advice, reviewing the proposed design, and checking the
system will contain compiled experimental data as well as the critically
evaluated recommendations. The printed volumes do have a limited number
of expressions and formats for the data. It is NIST's experience, however,
that printed text often contains subtle inconsistencies and ambiguities
that are identified only upon computerization.4 Additional
problems exist in making computerized data uniform, especially if the
definitive publication of the data is via printed page. For example,
it is common practice for small changes to be made directly onto page
proofs without alteration of the computer files that were input into
an automated typesetting system. Documentation of such changes is usually
nonexistent, which means that every number must be compared with the
printed page, and discrepancies investigated.
of the diverse data expressions, the search strategies are remarkably
simple. As is widely recognized, the solubility of substance A in substance
B can also be viewed as the solubility of substance B in substance A.
Therefore, there is no need to designate uniquely the solute and solvent
in designing the underlying database that stores the data, nor to constrain
search strategies unreasonably.
search strategies that will definitely be supported are as follows:
data on the solubility of substance A in substance B;
data on the solubility of A; and
data on the solubility of substances in substance B.
searching on the solubility data themselves will not be supported, but
depending on user needs, such as for liquid-liquid separations, this
capability could be added later. To support these searches, methods
for handling uncertainties need to be worked out. However, display of
data in different units will be supported. In the future, additional
features may be added, as requested by users, including performing calculations
and generating plots.
project to be successful, NIST and IUPAC will have to work closely together
on several issues, including system priorities, additional search strategies,
interface design, data quality, system functionality, and display of
results. The partnership is working successfully, as evidenced by the
smooth transition to publication of new volumes of the SDS. Both
parties look forward to a long relationship in order to make solubility
data readily available via the Web.
E.W. Washburn (Ed.). International Critical Tables of Numerical Data,
Physics, Chemistry, and Technology, published for the National Research
Council by McGraw-Hill, New York (1926-30).
T.E. Gills et al., "NIST mechanisms for disseminating measurements,"
submitted for inclusion in NIST Journal of Research, 102, no.
J.H. Westbrook. J. Chem. Info. Comput. Sci. 33, 617 (1993). John
Rumble Jr. is Chief of the NIST Standard Reference Data Program, Gaithersburg,
Rumble Jr. is Chief of the NIST Standard Reference Data Program,
Gaithersburg, Maryland, USA.
information about the SDS, including a list of volumes
published and in preparation, is available on the SDS
Web site. This site also contains email addresses of David
Gamsjäger, and Mark
Salomon, members of the IUPAC Subcommittee on Equilibrium
Data, who will gladly receive comments, questions, and proposals
for future volumes.
was originally published in Pure
and Applied Chemistry,
Vol. 73, No. 5, pp. 825-829, 2001 as part of the lecture presented
at the 9th IUPAC International Symposium on Solubility Phenomena, Hammamet,
Tunisia, 25-28 July 2000.