protactinium

pro·tac·tin·i·um

 (prō′tăk-tĭn′ē-əm)

n. Symbol Pa

A rare, extremely toxic, radioactive, lustrous, metallic element having more than 30 known isotopes and isomers, the most common of which is Pa-231 with a half-life of 32,760 years. Atomic number 91; atomic weight 231.036; melting point 1,572°C; specific gravity 15.37 (calculated); valence 2, 3, 4, 5. See Periodic Table.

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[prot(o)- + actinium (so called because it decays into actinium).]

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

protactinium

(ˌprəʊtækˈtɪnɪəm)

n

(Elements & Compounds) a toxic radioactive metallic element that occurs in uranium ores and is produced by neutron irradiation of thorium. Symbol: Pa; atomic no: 91; half-life of the most stable isotope, ²³¹Pa: 32 500 years; valency: 4 or 5; relative density: 15.37 (calc.); melting pt: 1572°C. Former name: protoactinium

Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

prot•ac•tin•i•um

(ˌproʊ tækˈtɪn i əm)

n.

a radioactive, metallic chemical element. Symbol: Pa; at. no.: 91.

[1915–20]

Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.

pro·tac·tin·i·um

(prō′tăk-tĭn′ē-əm)

Symbol Pa A rare, extremely toxic, radioactive metallic element of the actinide series that occurs in uranium ores. Its most common isotope has a half-life of 32,500 years. Atomic number 91. See Periodic Table.

The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Thesaurus

Noun

1.

protactinium - a short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead atomic number 91, protoactinium, Pa metal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.

Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.

Translations

протактиний

protaktinium

protactinium

Protactinium

protactinio

protaktiinium

protaktinium

protactinium

protaktinij

protoattinio

protactinium

protactinium

protactinium

протактиний

protaktinium

protaktinij

protaktinium

protactinium

n (Chem) → Protaktinium nt

Collins German Dictionary – Complete and Unabridged 7th Edition 2005. © William Collins Sons & Co. Ltd. 1980 © HarperCollins Publishers 1991, 1997, 1999, 2004, 2005, 2007