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A systematic element name is the temporary name assigned to an unknown or recently synthesized chemical element. A systematic symbol is also derived from this name.
In chemistry, a transuranic element receives a permanent name and symbol only after its synthesis has been confirmed. In some cases, such as the Transfermium Wars, controversies over the formal name and symbol have been protracted and highly political. In order to discuss such elements without ambiguity, the International Union of Pure and Applied Chemistry (IUPAC) uses a set of rules, adopted in 1978, to assign a temporary systematic name and symbol to each such element. This approach to naming originated in the successful development of regular rules for the naming of organic compounds.
IUPAC rules
The temporary names derive systematically from the element's atomic number, and apply only to 101 ≤ Z ≤ 999.[1] Each digit is translated into a "numerical root" according to the table. The roots are concatenated, and the name is completed by the suffix -ium. Some of the roots are Latin and others are Greek, to avoid two digits starting with the same letter (for example, the Greek-derived pent instead of the Latin quint to avoid confusion with quad for 4). There are two elision rules designed to prevent odd-looking names.
Digit | Root | Etymology | Symbol | Pronunciation |
---|---|---|---|---|
0 | nil | Latin nihil "nothing" | n | /nɪl/ |
1 | un | Latin unus "one" | u | /uːn/ |
2 | bi | Latin bis "twice" | b | /baɪ/ |
3 | tri | Latin tres "three" Greek tria "three" |
t | /traɪ/ |
4 | quad | Latin quattuor "four" | q | /kwɒd/ |
5 | pent | Greek pente "five" | p | /pɛnt/ |
6 | hex | Greek hex "six" | h | /hɛks/ |
7 | sept | Latin septem "seven" | s | /sɛpt/ |
8 | oct | Latin octo "eight" Greek okto ("eight") |
o | /ɒkt/ |
9 | en(n) | Greek ennea "nine" | e | /ɛn/ |
Suffix | -(i)um | Latin -um (neuter singular) | none | /-iəm/ |
If bi or tri is followed by the ending -ium (i.e. the last digit is 2 or 3), the result is -bium or -trium, not *-biium or *-triium. If enn is followed by nil (i.e. the sequence -90- occurs), the result is -ennil-, not *-ennnil-.
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Traditionally the suffix -ium was used only for metals (or at least elements that were expected to be metals), and other elements used different suffixes: halogens used -ine and noble gases used -on instead. However, systematic names use -ium for all elements regardless of group. Thus, elements 117 and 118 were ununseptium and ununoctium, not *ununseptine and *ununocton.[2] This does not apply to the trivial names these elements get once confirmed; thus, #117 and 118 are now tennessine and oganesson, respectively. For trivial names, all elements get the suffix -ium except those in group 17 (halogens), which get -ine; and group 18 (noble gases), which get -on. (Still, tennessine and oganesson are expected to behave quite differently from their lighter congeners.)
The systematic symbol is formed by taking the first letter of each root, capitalizing the first. This results in three-letter symbols instead of the one- or two-letter symbols for named elements. The rationale is that any scheme producing two-letter symbols will have to deviate from full systematicity to avoid collisions with the symbols of the permanently named elements.
The Recommendations for the Naming of Elements of Atomic Numbers Greater than 100 can be found here.
As of 2019, all 118 known elements have a permanent name and symbol.[3] Therefore, systematic names and symbols are now used only for the undiscovered elements beyond #118, oganesson. When such an element is discovered, it will keep its systematic name and symbol until its discovery meets the criteria of and is accepted by the IUPAC/IUPAP Joint Working Party, upon which the discoverers are invited to propose a permanent name and symbol. Once this name and symbol is proposed, there is still a comment period before they become official and replace the systematic name and symbol.
At the time the systematic names were recommended (1978), names had already been officially given to all elements up to atomic number 103, lawrencium. While systematic names were given for #101 (mendelevium), 102 (nobelium), and 103 (lawrencium), these were only as "minor alternatives to the trivial names already approved by IUPAC".[1] The following elements for some time only had systematic names as approved names, until their final replacement with trivial names after their discoveries were accepted.
Z | Systematic | Trivial | Year | |||
---|---|---|---|---|---|---|
Symbol | Name | Symbol | Name | Undisputed synthesis first published | Named | |
104 | Unq | Unnilquadium | Rf | Rutherfordium | 1969 | 1997 |
105 | Unp | Unnilpentium | Db | Dubnium | 1970 | 1997 |
106 | Unh | Unnilhexium | Sg | Seaborgium | 1974 | 1997 |
107 | Uns | Unnilseptium | Bh | Bohrium | 1981 | 1997 |
108 | Uno | Unniloctium | Hs | Hassium | 1984 | 1997 |
109 | Une | Unnilennium | Mt | Meitnerium | 1982 | 1997 |
110 | Uun | Ununnilium | Ds | Darmstadtium | 1995 | 2003 |
111 | Uuu | Unununium | Rg | Roentgenium | 1995 | 2004 |
112 | Uub | Ununbium | Cn | Copernicium | 1996 | 2010 |
113 | Uut | Ununtrium | Nh | Nihonium | 2004 | 2016 |
114 | Uuq | Ununquadium | Fl | Flerovium | 1999 | 2012 |
115 | Uup | Ununpentium | Mc | Moscovium | 2004 | 2016 |
116 | Uuh | Ununhexium | Lv | Livermorium | 2000 | 2012 |
117 | Uus | Ununseptium | Ts | Tennessine | 2010 | 2016 |
118 | Uuo | Ununoctium | Og | Oganesson | 2006 | 2016 |
References
- ^ a b "Element names >100".
- ^ Koppenol, W. (2016). "How to name new chemical elements" (PDF). Pure and Applied Chemistry. DeGruyter. doi:10.1515/pac-2015-0802. hdl:10045/55935. S2CID 102245448.
- ^ "IUPAC Announces the Names of the Elements 113, 115, 117, and 118". IUPAC. 2016-11-30. Retrieved 2016-11-30.
External links
- "IUPAC Provisional Recommendations: IR-3: Elements and Groups of Elements" (PDF). IUPAC. March 2004.
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