# "Elementium" and its oxide "Elementia" - whence this pattern?

**URL:** <https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240>\
**Category:** Factual Questions\
**Created:** [February 5, 2016, 4:19pm UTC](https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240 "2016-02-05T16:19:18Z")\
**Posts on this page:** 11\
**Page:** 1

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**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\
**Post date:** [February 5, 2016, 4:19pm UTC](https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240/1 "2016-02-05T16:19:18Z")

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Many metallic elements and their oxides are named in pairs where the metal itself ends in “um” but that’s replaced by “a” for the oxide. For example, there are aluminum and alumina, titanium and titania, or hafnium and hafnia. How did this come about?

According to the Wikipedia article for magnesium,  
“The name magnesium originates from the Greek word for a district in Thessaly called Magnesia.”

Ah, so the word for the oxide happened first and the metal itself was derived from it.

But I don’t think all the oxide names are also words or names unto themselves. Was magnesium the prototype for this? Is there maybe a false etymology or something?

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**Author:** ![glowacks](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/glowacks/32/5548_2.png) [@glowacks](https://boards.straightdope.com/u/glowacks)\
**Post date:** [February 6, 2016, 4:53am UTC](https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240/2 "2016-02-06T04:53:14Z")

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I would suggest that it’s from the 2nd declension of neuter nouns in Latin, which are -um in the singular and -a in the plural. Just the first thing that came off the top of my head.

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**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\
**Post date:** [February 6, 2016, 4:20pm UTC](https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240/3 "2016-02-06T16:20:59Z")

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Props on “whence” (and the query in general). Also to the top of **glowacks** ’s head.

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**Author:** ![rowrrbazzle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rowrrbazzle/32/414_2.png) [@rowrrbazzle](https://boards.straightdope.com/u/rowrrbazzle)\
**Post date:** [February 7, 2016, 4:20am UTC](https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240/4 "2016-02-07T04:20:13Z")

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From the OED:

> [@](#):
>
> Etymology: A borrowing from Latin, combined with an English element. Etymons: Latin _alumina_ , -A suffix1.  
> \< post-classical Latin _alumina_ (1787) \< classical Latin _alūmin-_ , _alūmen_ alum n.1 + -A suffix1, formed by the French chemical nomenclators after e.g. \*soda \*and _magnesia_, its character as the earth of alum having been proved by A. S. Marggraf in 1754 (compare _earth of alum n._ at _earth n.1_ Phrases 6, German _Alaunerde_); other proposed names were _arga n._ and _argil n._ Compare slightly earlier _alumine n._ and its French etymon.

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**Author:** ![kaylasdad99](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kaylasdad99/32/3398_2.png) [@kaylasdad99](https://boards.straightdope.com/u/kaylasdad99)\
**Post date:** [February 7, 2016, 8:17am UTC](https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240/5 "2016-02-07T08:17:05Z")

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> [@Napier](#):
>
> Many metallic elements and their oxides are named in pairs where the metal itself ends in “um” but that’s replaced by “a” for the oxide. For example, there are aluminum and alumina, titanium and titania, or hafnium and hafnia. How did this come about?
> 
> According to the Wikipedia article for magnesium,  
> “The name magnesium originates from the Greek word for a district in Thessaly called Magnesia.”

So . . . Milk of Magnesia comes from cows grazed in that district in Thessaly?

Also, is there such a thing as Cheese of Magnesia?

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**Author:** ![kaylasdad99](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kaylasdad99/32/3398_2.png) [@kaylasdad99](https://boards.straightdope.com/u/kaylasdad99)\
**Post date:** [February 7, 2016, 8:20am UTC](https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240/6 "2016-02-07T08:20:35Z")

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> [@Leo\_Bloom](#):
>
> Props on “whence” (and the query in general). Also to the top of **glowacks** ’s head.

Props to the top of **glowacks** ’s head? You mean like one of those beanies?

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**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\
**Post date:** [February 7, 2016, 12:17pm UTC](https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240/7 "2016-02-07T12:17:29Z")

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> [@rowrrbazzle](#):
>
> From the OED:

I take this to indicate that the appearance of a pattern here is wrong, and that the similarity of forms for alumina and magnesia is only coincidence? How about all the others?

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**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\
**Post date:** [October 17, 2016, 5:44am UTC](https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240/8 "2016-10-17T05:44:40Z")

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> [@Napier](#):
>
> I take this to indicate that the appearance of a pattern here is wrong, and that the similarity of forms for alumina and magnesia is only coincidence? How about all the others?

I don’t think you read it right. The way I read it, metallic elements ending with -ium are named in the pattern established by sodium and magnesium. Somewhere I read that that ending is now required by the IUPAC in naming metallic elements while non-metallic elements get other endings.

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**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\
**Post date:** [October 17, 2016, 10:23pm UTC](https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240/9 "2016-10-17T22:23:50Z")

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This might be informative at least as to the formation of the oxide variants: [IUPAC nomenclature of inorganic chemistry - Wikipedia](https://en.wikipedia.org/wiki/IUPAC_nomenclature_of_inorganic_chemistry)

As to the element names try [List of chemical element name etymologies - Wikipedia](https://en.wikipedia.org/wiki/List_of_chemical_element_name_etymologies)

Neither of these are the whole story but I bet they get you some good entry points.

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**Author:** ![Cartoonacy](https://avatars.discourse-cdn.com/v4/letter/c/848f3c/32.png) [@Cartoonacy](https://boards.straightdope.com/u/Cartoonacy)\
**Post date:** [October 19, 2016, 8:44pm UTC](https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240/10 "2016-10-19T20:44:43Z")

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> [@kaylasdad99](#):
>
> Also, is there such a thing as Cheese of Magnesia?

I don’t know. But I do know that if you mix Milk of Magnesia with orange juice, you get a Phillips Screwdriver.

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**Author:** ![jtur88](https://avatars.discourse-cdn.com/v4/letter/j/e9c0ed/32.png) [@jtur88](https://boards.straightdope.com/u/jtur88)\
**Post date:** [October 19, 2016, 11:52pm UTC](https://boards.straightdope.com/t/elementium-and-its-oxide-elementia-whence-this-pattern/745240/11 "2016-10-19T23:52:55Z")

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Scientists established a lot of nomenclaure rules a long time ago, to make consistent sense of the language of science. Another example is the -ic and -ous suffixes for metals in compounds, depending on the valence. Ferric, Mercuric, cupric, etc. refer to compounds of the higher valence,and ferrous, mercurous, cuprous for the lower valence. Similarly for acids, such as sulfuric and sulfurous.

For examples like those described by the OP, the ending forms of the names of chemicals are formed exactly for the purpose of showing the relationshp between the two.