Some textbooks write the electron configuration for platinum (Pt) as $\ce{[Xe] 4f^14 5d^9 6s^1}$. However, some also write it as $\ce{[Xe] 4f^14 5d^8 6s^2}$. Which is correct?

I hope someone can help me with an authoritative source.


1 Answer 1


The NIST Atomic Spectra Database,[1] which is as authoritative as it gets, shows that $\ce{5d^9 6s^1}$ is the correct ground-state electronic configuration for platinum.

Various inorganic textbooks also say the same. Wikipedia cites Meissler and Tarr for this table: https://en.wikipedia.org/wiki/Electron_configuration#Other_exceptions_to_Madelung's_rule

  1. Kramida, A., Ralchenko, Yu., Reader, J., and NIST ASD Team (2020). NIST Atomic Spectra Database (ver. 5.8), [Online]. Available: https://physics.nist.gov/asd [2021, January 6]. National Institute of Standards and Technology, Gaithersburg, MD. DOI: https://doi.org/10.18434/T4W30F

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