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hahnium

[hah-nee-uh m]
noun Chemistry, Physics.
  1. a proposed name for dubnium. Symbol: Ha
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Origin of hahnium

1965–70; after German chemist O. Hahn; see -ium
Also called unnilpentium, element 105.

unnilpentium

[yoo-nil-pen-tee-uh m]
noun Chemistry, Physics.
  1. a former name of dubnium. Symbol: Unp
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Origin of unnilpentium

1975–80; < Latin ūn(us) one + nīl nothing + Greek pént(e) five + New Latin -ium -ium
Also called element 105.Formerly hahnium.

dubnium

[doob-nee-uh m, duhb-]
noun Chemistry, Physics.
  1. a superheavy, synthetic, radioactive element with a very short half-life. Symbol: Db; atomic number: 105.
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Origin of dubnium

named after Dubna, the town in Russia where it was first produced; see -ium
Formerly hahnium, unnilpentium, element 105.

element 105

noun Chemistry, Physics.
  1. dubnium.
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Origin of element 105

First recorded in 1975–80
Formerly unnilpentium, hahnium.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for hahnium

hahnium

noun
  1. a name once advanced by the American Chemical Society for a transuranic element, artificially produced from californium, atomic no: 105; half-life of most stable isotope, 262 Ha: 40 secondsNow called dubnium
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Word Origin

C20: named after Otto Hahn

dubnium

noun
  1. a synthetic transactinide element produced in minute quantities by bombarding plutonium with high-energy neon ions. Symbol: Du; atomic no 105See hahnium
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Word Origin

C20: after Dubna, where it was first reported
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

hahnium in Science

dubnium

[dōōbnē-əm]
Db
  1. A synthetic, radioactive element that is produced from californium, americium, or berkelium. Its most long-lived isotopes have mass numbers of 258, 261, 262, and 263 with half-lives of 4.2, 1.8. 34, and 30 seconds, respectively. Atomic number 105. See Periodic Table.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.