In The Elements by John Emsley there appears the following in the description of most Rare Earths:

 

"...of the so-called Rare Earth group (more correctly termed the lanthanides [or actinides])"

 

Is there some doubt about the correct classification of the lanthides and actinides?

Not that I'm aware of. They are group together in the f-block and the two different names refer to whether the first f-orbital of the second f-orbital is the valence one

Not that I'm aware of. They are group together in the f-block and the two different names refer to whether the first f-orbital of the second f-orbital is the valence one

 

Thanks for clarifying Emsley's statement. Emsley could avoid creating doubts by explaining this more clearly as group and sub-groups.

It was perfectly clear to me what he meant.

 

Calling them "rare earths" when most of them are not rare and none of them is an earth seems unhelpful so calling them the lanthanides or actinides is more correct.

The difference is between a technically precise term - Lanthanides and Actinides, and an informal, 'popular' term - rare earths. Like John I am puzzled as to why there would be any confusion.

The difference is between a technically precise term - Lanthanides and Actinides, and an informal, 'popular' term - rare earths. Like John I am puzzled as to why there would be any confusion.

 

It is because an untrained amateur like myself wants to know the reason for Emsley's wording, the reply given by Horza2002 is detailed and precise it is exactly what I wanted, if only every 'expert' were as competent; neither Emsley or any of the university web sites that use the 'rare earth' term state that it is an informal term, therein lies the confusion.

It is because an untrained amateur like myself wants to know the reason for Emsley's wording, the reply given by Horza2002 is detailed and precise it is exactly what I wanted, if only every 'expert' were as competent; .

The reason is implicit in the language.

Horza2002 does not explain the reason for Emsley's wording, but I am pleased you found his reply useful.

I'll take the last remark as a side swipe at my own contribution. I'll seek not to inconvenience you on future threads.

The reason is implicit in the language.

Horza2002 does not explain the reason for Emsley's wording, but I am pleased you found his reply useful.

I'll take the last remark as a side swipe at my own contribution. I'll seek not to inconvenience you on future threads.

 

No side swipe intended, from my layman's reading Emsley seem to be implying that the term rare earth is incorrect or of dubious value, clearly professionals make a different interpretation of the phrase Emsley uses. Your reply is just as welcome as Horza2002, but again from a layman's viewpoint Horza2002 reply has an educational value which, with respect; is missing from "The reason is implicit in the language".

It was perfectly clear to me what he meant.

 

Calling them "rare earths" when most of them are not rare and none of them is an earth seems unhelpful so calling them the lanthanides or actinides is more correct.

 

I'm more comfortable calling them Lanthanoids and Actinoids so as to avoid confusion about the negatively charged ions of Lanthanum and Actinium.

No side swipe intended, from my layman's reading Emsley seem to be implying that the term rare earth is incorrect or of dubious value, clearly professionals make a different interpretation of the phrase Emsley uses. Your reply is just as welcome as Horza2002, but again from a layman's viewpoint Horza2002 reply has an educational value which, with respect; is missing from "The reason is implicit in the language".

My apologies for misunderstanding you. I should have a) read what you wrote more carefully, b) not jumped to a concussion.

My apologies for misunderstanding you. I should have a) read what you wrote more carefully, b) not jumped to a concussion.

 

Try not to jump while in a low-ceiling room. That should avoid the concussions.