ununoctium

See also: Ununoctium

English

Etymology

Systematic element name, from un- +‎ un- +‎ oct- +‎ -ium.

Pronunciation

• Audio:

  (file)

Noun

ununoctium (uncountable)

1. (dated) The systematic element name for the chemical element with atomic number 118 (symbol Uuo); now named oganesson.
   • 2015 December 30, “Discovery and Assignment of Elements with Atomic Numbers 113, 115, 117 and 118”, in IUPAC‎^[1]:

     “The chemistry community is eager to see its most cherished table finally being completed down to the seventh row. IUPAC has now initiated the process of formalizing names and symbols for these elements temporarily named as ununtrium, (Uut or element 113), ununpentium (Uup, element 115), ununseptium (Uus, element 117), and ununoctium (Uuo, element 118)” said Professor Jan Reedijk, President of the Inorganic Chemistry Division of IUPAC.

   • 2016 March 1, Willem H. Koppenol, John Corish, Javier García-Martínez, Juris Meija and Jan Reedijk, “How to name new chemical elements (IUPAC Recommendations 2016)”, in Pure and Applied Chemistry‎^[2], volume 88, number 4, →DOI, archived from the original on 11 November 2025, page 404:

     Prior to and during the naming process, the element may be referred to by its atomic number, for example as in ‘element 118’, or by its provisional systematic name, ‘ununoctium’.

Synonyms

• eka-radon
• oganesson

Coordinate terms

• Previous: tennessine Ts;
• Next: ununennium Uue

Translations

chemical element

• Arabic: أُنُون أُوكْتِيُوم m (ʔunun ʔuktiyum)
• Catalan: ununocti (ca) m
• Dutch: ununoctium (nl) n
• Esperanto: ununoktio (eo)
• Estonian: ununoktium
• Finnish: ununoktium (fi)
• French: ununoctium (fr) m
• Galician: ununoctio (gl) m
• German: Ununoctium (de) n
• Greek: ουνουνόκτιο n (ounounóktio)
• Hungarian: ununoktium (hu)
• Italian: ununoctio (it) m
• Korean: 우누녹튬 (ununoktyum)
• Malay: ununoktium
• Norwegian: ununoctium
• Polish: ununoctium (pl) m
• Portuguese: ununóctio (pt) m
• Romanian: ununoctiu (ro) n
• Russian: унуно́ктий (ru) m (ununóktij)
• Serbo-Croatian:

  Cyrillic: унуноктиј m, унуноктијум m

  Roman: ununoktij m, ununoktijum m

• Spanish: ununoctio (es) m
• Swedish: ununoktium (sv)
• Thai: อูนอูนออกเทียม (ūnūnòktiam)
• Ukrainian: унуно́ктій m (ununóktij)

Danish

Noun

ununoctium

1. oganesson

Dutch

Chemical element
Uuo
Previous: ununseptium (Uus)
Next: ununennium (Uue)

Pronunciation

• Audio:

  (file)

Noun

ununoctium n (uncountable, no diminutive)

1. ununoctium

Latin

Etymology

Derived from ūn(us) (“one”) + ūn(us) + oct(ō) (“eight”) +‎ -ium (chemical element suffix), in reference to the element's atomic number (118).

Pronunciation

• (Classical Latin) IPA^(key): [uː.nuːˈnɔk.ti.ũː]
• (modern Italianate Ecclesiastical) IPA^(key): [u.nuˈnɔk.t͡si.um]

Noun

ūnūnoctium n (genitive ūnūnoctiī); second declension

1. (New Latin) ununoctium

Declension

Second-declension noun (neuter).

	singular	plural
nominative	ūnūnoctium	ūnūnoctia
genitive	ūnūnoctiī	ūnūnoctiōrum
dative	ūnūnoctiō	ūnūnoctiīs
accusative	ūnūnoctium	ūnūnoctia
ablative	ūnūnoctiō	ūnūnoctiīs
vocative	ūnūnoctium	ūnūnoctia

Descendants

• Italian: ununoctio

Slovak

Chemical element
Uuo
Previous: ununseptium (Uus)
Next: ununennium (Uue)

Noun

ununoctium n (genitive singular ununoctia, declension pattern of mesto)

1. ununoctium (element)