# Talk:Praseodymium

Article changed over to new Wikipedia:WikiProject Elements format by schnee. Elementbox converted 11:00, 10 July 2005 by Femto (previous revision was that of 13:13, 9 July 2005). 9 July 2005

Data for the table was obtained from the sources listed on the subject page and Wikipedia:WikiProject Elements but was reformatted and converted into SI units.

In the NFPA 704 diamond of praseodymium, Health, Flammability and Reactivity are 0, 4, and 4 respectively. But for neodymium it is 2, 0, and 0. 
A flammability of 4 means that it is easily dispersed in the air and is easy to burn (such as methane), and a reactivity of 4 means that it can explode quickly under normal temperature and pressure (such as TNT)  .
I checked the history and found no trace of vandalism. Is this true? I can't find relevant information.--DoroWolf (talk) 02:49, 9 January 2022 (UTC)

The article says "Like most other metals in the lanthanide series, praseodymium usually only uses three electrons as valence electrons, as afterward the remaining 4f electrons are too strongly bound: this is because the 4f orbitals penetrate the most through the inert xenon core of electrons to the nucleus, followed by 5d and 6s, and this increases with higher ionic charge."
I don't see any 5d electrons in praseodymium.  Should that be 4d, or what? Vaughan Pratt (talk) 19:08, 28 July 2023 (UTC)

Also, Pr only has 3 f electrons to start with, so it doesn't have any remaining. Some of the other lanthanides have 5d and 6s electrons, that's where this comes from. This statement has been copied and pasted from a general description of lanthanides and doesn't describe the situation in Pr very well. Owensumm (talk) 20:04, 10 May 2024 (UTC)
Nope, it is correct. You're forgetting the 6s electrons (since Pr is 4f35d06s2 as a single atom). And also, 4f and 5d are very close in energy, so 5d easily becomes occupied in chemical environments even if it's not occupied in the bare atom. Double sharp (talk) 03:07, 8 September 2024 (UTC)