Terms of Service

By using Periodicium ("the Service"), you accept and agree to be bound by these terms. If you do not agree with them, please do not use the Service.

Periodicium is a web application presenting reference data for the chemical elements and their nuclides in form of an interactive periodic table. It is provided free of charge and requires no account.

You agree to use the Service only for lawful purposes and in accordance with these Terms. You agree not to:

• Use the Service for any illegal or unauthorized purpose
• Attempt to gain unauthorised access to the Service or the systems behind it
• Interfere with or disrupt the Service, or place an automated load on it that degrades it for others
• Use the feedback form to harass, abuse or harm anyone, or to submit spam

The data is compiled from the published sources listed below and is provided for reference and educational use. It is presented as accurate to the best of our knowledge, but no warranty of accuracy or completeness is given, values are rounded for display, and some properties are unmeasured or predicted rather than experimental.

Do not rely on Periodicium where an error could cause harm. It is not a substitute for a primary source, a safety data sheet or professional judgement, in particular for handling radioactive or toxic materials, for medical or dosimetric purposes, or for any engineering or safety-critical calculation.

Element and nuclear data is compiled from the references below rather than measured here. Where a source sets licence terms, they are stated.

• NUBASE2020 Half-lives, decay modes and branching ratios, spins and parities, mass excesses, isotopic abundances and discovery years for every known nuclide. Cite as F. G. Kondev et al., Chinese Physics C 45, 030001 (2021).
• NIST Atomic Spectra Database Emission line wavelengths and relative intensities, ionization stages, electron configurations, term symbols and level energies. A work of the U.S. government, used with attribution to NIST.
• PubChem Electronegativity values, and an independent check on the atomic masses, densities, and melting and boiling points. Public domain, published by the U.S. National Library of Medicine.
• IUPAC Element names, symbols and standard atomic weights, and the group and period numbering.
• Wikipedia The thermodynamic and electromagnetic properties of each element and the molar ionization energies. CC BY-SA 4.0. The data shown here that is drawn from Wikipedia is shared under the same licence.

Some properties are derived rather than taken from a source.

Periodicium's name, design, features and source code belong to Kyrylo Tymchyshyn.

The underlying scientific data belongs to the sources named above and remains subject to their terms. Nothing here grants you rights in that data beyond what those sources allow.

The Service is provided "as is" and "as available", without warranties of any kind. We do not guarantee that it will be available at all times, that it will be free of errors, or that any part of it will be kept in its present form.

We may update these terms from time to time. Any change is published on this page with a new "Last updated" date, and continuing to use the Service after that constitutes acceptance of the updated terms.

To the extent permitted by law, Periodicium and its owner are not liable for any indirect, incidental, special, consequential or punitive damages, nor for any loss arising from reliance on the data presented, resulting from your use of the Service.

If any provision of these terms is found invalid or unenforceable, the remaining provisions stay in full force.

If you have a question about these terms, send it through the feedback form in the application menu.

You can also contact us by email at support@periodicium.com.