Thermochemical Database (TDB) Project

Problems accessing the TDB web pages

This page aims to answer some common question about accessing the TDB web pages and the documents displayed there.

How do I get a user name and password for access?

You must register to get a user name and password to access the TDB online database. You can register here. See also the general instructions on how to access and register for information about this.

I signed up using the registration form, but I was never sent a user name and a password. What's the problem?

When you fill out the registration form, be careful to read ALL of it, all the way to the bottom. To obtain a user name and a password for the TDB database, you have to fill out the part after the headline "Additional Database Access Registration", and check the checkbox for "Chemical Thermodynamics". Note that you must be a citizen of an NEA member country to be granted access.

If you don't fill out this last part of the form, you will be registered as a user, but will not be sent a user name and a password.

If you think you have filled out the form and registered correctly, but still don't get a password and a user name within a week or so, please contact .

I try to use my user name and password, but they are not accepted. What do I do?

This problem can have several causes. Please verify that

  1. You are not trying to access a part of the website that is not for public use. To access the review review group pages, you have to be a member of the review team in question or of the TDB Management Board or Executive Group. These web pages contain only internal material (drafts, mailing list archives etc.) which is not of public interest, and cannot be accessed by people who are not part of the project.
  2. You have waited at least 24 hours (not counting weekends) after obtaining a user name and password before trying to access the pages.
  3. You have entered your password and user name using all lower-case letters. The password and user name are case-sensitive, and entering i. e. "SMITH" or "Smith" instead of "smith" as your user name will not work. Your user name is probably your last name only in lower-case, but for obvious reasons this is not always true (there are many "Smith"s out there).
  4. You are using the latest and greatest version of your internet browser. Some older versions of certain browsers have problems transmitting the user name and password information correctly.
  5. You are not trying to access the NEA web pages between 21:00 and 22:00 CET (=GMT+1 wintertime, GMT+2 during the summer). The web pages are normally automatically updated at that time, which may cause access problems.
Sometimes there are temporary problems with internet connections. Please wait 24 hours and try again before you decide that you cannot access the web pages. If all else fails, send mail to and ask for help. We try to answer as soon as possible, but cannot always guarantee a swift response due to the workload.

I have forgotten my user name and/or password. What do I do?

Send an e-mail to and ask for the required information. Please use the e-mail address you used when you registered to send the request.

NB: If you already have a user name and a password, and have merely forgotten what they are, do not re-register to get a new password and user name. This will only confuse our registration system, and may cause delays in making your account functional again. Please send an e-mail instead.

There used to be data about lots of different compounds and complexes available in the TDB database. Now there is only data for some compounds left. What happened to the rest?

At the beginning of the TDB project, it was planned to scan most of the available literature for measurements, estimates and compilations of thermochemical data of relevance to the project. These "compiled" data were then inserted in the TDB database, and were previously available through the TDB online database retrieval. It should be emphasised, that these "compiled" data were entered directly from the available literature without any critical evaluation whatsoever. The idea was to facilitate the work of the different review groups within the project by providing a cover-all initial literature search. However, as NEA resources for the project were decreased over time, it became impossible to continue this work. Literature scanning is now done separately by each review team for the publications of interest to their particular review report and not by the NEA. It is now many years since this kind of general compilation was done actively by the NEA. When the online access to the TDB database was changed earlier this year, it was decided to include only the selected data, i. e. data that has been evaluated by the review teams and published in the review reports. This was done for two reasons:

  1. Providing "compiled" data alongside with the selected, evaluated data could easily confuse people and give them the impression that all the data were endorsed by the TDB project.
  2. For reasons outlined above, the set of merely "compiled" data in the database was in any case badly out of date, and did not in any way provide a complete literature coverage.

Related links

TDB introduction

Latest project news

General information

Other thermochemical database sites

E-mail contact: 

Related links

TDB Phase II home page
TDB Phase III home page
TDB Phase IV home page

Last reviewed: 6 January 2014