[ yoo-nil-kwod-ee-uh m ]
/ ˌyu nɪlˈkwɒd i əm /

noun Chemistry, Physics.

former name of rutherfordium. Symbol: Unq



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Also called element 104.

Origin of unnilquadium

1975–80; < Latin ūn(us) one + nīl nothing + quad(ri)- + New Latin -ium -ium

Definition for unnilquadium (2 of 3)

[ ruhth-er-fawr-dee-uh m, -fohr-, ruhth- ]
/ ˌrʌð ərˈfɔr di əm, -ˈfoʊr-, ˌrʌθ- /

noun Chemistry, Physics.

a superheavy, synthetic, radioactive element with a very short half-life. Symbol: Rf; atomic number: 104.
Formerly unnilquadium, element 104.

Origin of rutherfordium

1969; named after English physicist Ernest Rutherford; see -ium

Definition for unnilquadium (3 of 3)

element 104

noun Chemistry, Physics.

Formerly unnilquadium.

Origin of element 104

First recorded in 1975–80
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for unnilquadium

/ (ˌrʌðəˈfɔːdɪəm) /


a transactinide element produced by bombarding californium-249 nuclei with carbon-12 nuclei. Symbol: Rf; atomic number.: 104; atomic wt: 261Name in the former Soviet Union: kurchatovium

Word Origin for rutherfordium

C20: named after Ernest Rutherford
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for unnilquadium

[ rŭð′ər-fôrdē-əm ]


A synthetic, radioactive element that is produced by bombarding plutonium with carbon or neon ions. Its most stable isotope is Rf 261 with a half-life of 62 seconds. Atomic number 104. See Periodic Table.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.