Editor John Rumble answers your questions
How is the Handbook kept up-to-date?
We have a group of outstanding authors, experts in their own fields, who do most of the compilation and quality assessment. Many of these authors work at data centers at the National Institute of Standards and Technology, or other well-known research organizations, and can draw on those data resources in their work. Others have often compiled and evaluated data on a specific topic for their own research interests. They are willing to share those data collections with the Handbook to help advance science.
Also, in most fields, the cycle of improved measurements is three to five years, and most of our data tables are reviewed and updated in that time frame. Consequently, every year the new edition has between 15-25% updated tables, which is why it is important for our users to keep their volume current. I should note that a few topics, such as our Table of Isotopes, are updated almost every year. During the last three years, we have updated many important topics, including high-temperature superconductors, semiconductor diffusion, properties of refrigerants, and chemical safety.
Why buy the Handbook today where seemingly you can find anything on the Web?
It is a mixture of the diversity of our data content – over 400 separate scientific topics – combined with our dedication to quality. Let me expand on both these points. Every day, scientists in the course of their research and other activities require a wide variety of data. While most of the data they require can be found with great effort in the original literature, in almost every case, they are not able to assess the quality of the reported measurements and equally unable to choose among conflicting results.
The Handbook has worked with over 100 experts who collect the data in their respective fields, evaluate their quality according to well-established criteria, and then create the data tables found in the Handbook using the data they judge to be most reliable and of highest quality. Not only are the data easily found in one convenient Print volume or in our easy-to-use Online database, but also users can be confident these data are the best available.
What changes have you made to the Handbook in recent years?
The 104th Edition of the Handbook has been completely reorganized to meet the needs of today’s scientists. The first section has property data on the elements, organic and inorganic compounds, water, bio-medical compounds, and polymers. Other sections focus on applications of chemical and physical data, data of importance in laboratory work, and information of units and nomenclature. The purpose of the reorganization is to make sure users can easily find all data on related subjects.
One other change that especially impacts online users is improved capability for substance searching. Many modern chemical substances and advanced materials use nomenclature beyond traditional chemical notation. With these search improvements, users can be confident that find all relevant data within the Handbook.
Who uses the handbook?
We recognize our user community represents the broadest possible set of chemists, physicists, and other scientists, many of them working in specialisms – for example, environmental scientists, toxicologist, green chemists, nanotechnology, energy researchers, etc.
Also some of the heaviest users of the Handbook are students at all levels, undergraduates, graduate students, and those in high school. We are creating free user guides that help students and their teachers understand better how the Handbook is an invaluable source for chemistry and physics problem sets. Here I also want to mention that we are working to improve our applied physics coverage in the same way that we are improving our applied chemistry and will be producing similar guides for physics students.
What do you see as the challenges of the future?
Probably the greatest challenge is the tsunami of data that is a result of advanced instrumentation, our improved ability to synthesize and purify chemical and materials, and, quite simply, the number of researchers who are publishing papers. Obviously, all new data cannot be included in the Printed Handbook, but our Online database system is capable of handling very large data volumes. More important is the question of how to assess the quality of individual data values within this massive flow. One key issue is that rarely does a single measurement yield a long-lasted property value, yet most measurements are not repeated, Assessing the quality of a single measure is a big challenge.
The second challenge is one of the emerging of so-called knowledge discovery tools – machine learning, artificial intelligence, etc. These tools require fairly large volumes of high-quality data. Specialized data repositories such as those found in the area of crystallographic structure will be heavily used. At the same time, many complex systems and phenomena depend on multiple properties, so resources such as the handbook, which cover many properties will be sought by these tools. How to interface with them will be an interesting activity.
Finally, I need to mention that modern modelling techniques, whether based on first-principles quantum chemistry, or more heuristic models, have advanced to begin producing accurate property data. To date, however, there is virtually no accepted methodology for determining or expressing the uncertainties for modeling results. The Handbook contains few calculated property values not based on physical measurements. That will change in the coming decade, and the editors are working with the authors to determine how to assess the quality of model results, independent of comparison with experimental results.