Isotopes of chromium
2527049
208514029
2008-04-27T12:46:54Z
Vina-iwbot
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robot Adding: [[zh:鉻的同位素]]
Naturally occurring '''[[chromium]]''' ('''Cr''') is composed of three stable [[isotope]]s; <sup>52</sup>Cr, <sup>53</sup>Cr, and <sup>54</sup>Cr with <sup>52</sup>Cr being the most abundant (83.789% [[natural abundance]]). Nineteen [[radioisotope]]s have been characterized with the most stable being <sup>50</sup>Cr with a [[half-life]] of (more than) 1.8x10<sup>17</sup> years, and <sup>51</sup>Cr with a half-life of 27.7 days. All of the remaining [[radioactive]] isotopes have half-lives that are less than 24 hours and the majority of these have half-lives that are less than 1 minute. This element also has 2 [[meta state]]s.
<sup>53</sup>Cr is the [[radiogenic]] decay product of <sup>53</sup>[[manganese|Mn]]. Chromium [[isotope|isotopic]] contents are typically combined with [[manganese]] isotopic contents and have found application in [[isotope geology]]. [[manganese|Mn]]-Cr isotope ratios reinforce the evidence from <sup>26</sup>[[Aluminium|Al]] and <sup>107</sup>[[Palladium|Pd]] for the early history of the [[solar system]]. Variations in <sup>53</sup>Cr/<sup>52</sup>Cr and Mn/Cr ratios from several meteorites indicate an initial <sup>53</sup>Mn/<sup>55</sup>Mn ratio that suggests Mn-Cr isotope systematics must result from in-situ decay of <sup>53</sup>Mn in differentiated planetary bodies. Hence <sup>53</sup>Cr provides additional evidence for [[nucleosynthesis|nucleosynthetic]] processes immediately before coalescence of the solar system.
The isotopes of chromium range in [[atomic weight]] from 43 [[atomic mass unit|u]] (<sup>43</sup>Cr) to 67 u (<sup>67</sup>Cr). The primary [[decay mode]] before the most abundant stable isotope, <sup>52</sup>Cr, is [[electron capture]] and the primary mode after is [[beta decay]].
<br />Standard atomic mass: 51.9961(6) [[unified atomic mass unit|u]]
== Table ==
{| class="wikitable" style="font-size:95%; white-space:nowrap"
! rowspan="2" | nuclide<br />symbol
! Z([[proton|p]])
! N([[neutron|n]])
! <br />isotopic mass (u)<br />
! rowspan="2" | half-life
! rowspan="2" | nuclear<br />spin
! rowspan="2" | representative<br />isotopic<br />composition<br />(mole fraction)
! rowspan="2" | range of natural<br />variation<br />(mole fraction)
|-
! colspan="3" | excitation energy
|-
| <sup>42</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 18
| 42.00643(32)#
| 14(3) ms [13(+4-2) ms]
| 0+
|
|
|-
| <sup>43</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 19
| 42.99771(24)#
| 21.6(7) ms
| (3/2+)
|
|
|-
| <sup>44</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 20
| 43.98555(5)#
| 54(4) ms [53(+4-3) ms]
| 0+
|
|
|-
| <sup>45</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 21
| 44.97964(54)
| 50(6) ms
| 7/2-#
|
|
|-
| style="text-indent:1em" | <sup>45m</sup>Cr
| colspan="3" style="text-indent:2em" | 50(100)# keV
| 1# ms
| 3/2+#
|
|
|-
| <sup>46</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 22
| 45.968359(21)
| 0.26(6) s
| 0+
|
|
|-
| <sup>47</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 23
| 46.962900(15)
| 500(15) ms
| 3/2-
|
|
|-
| <sup>48</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 24
| 47.954032(8)
| 21.56(3) h
| 0+
|
|
|-
| <sup>49</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 25
| 48.9513357(26)
| 42.3(1) min
| 5/2-
|
|
|-
| <sup>50</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 26
| 49.9460442(11)
| STABLE [>1.3E+18 a]
| 0+
| 0.04345(13)
| 0.04294-0.04345
|-
| <sup>51</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 27
| 50.9447674(11)
| 27.7025(24) d
| 7/2-
|
|
|-
| <sup>52</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 28
| 51.9405075(8)
| STABLE
| 0+
| 0.83789(18)
| 0.83762-0.83790
|-
| <sup>53</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 29
| 52.9406494(8)
| STABLE
| 3/2-
| 0.09501(17)
| 0.09501-0.09553
|-
| <sup>54</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 30
| 53.9388804(8)
| STABLE
| 0+
| 0.02365(7)
| 0.02365-0.02391
|-
| <sup>55</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 31
| 54.9408397(8)
| 3.497(3) min
| 3/2-
|
|
|-
| <sup>56</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 32
| 55.9406531(20)
| 5.94(10) min
| 0+
|
|
|-
| <sup>57</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 33
| 56.943613(2)
| 21.1(10) s
| (3/2-)
|
|
|-
| <sup>58</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 34
| 57.94435(22)
| 7.0(3) s
| 0+
|
|
|-
| <sup>59</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 35
| 58.94859(26)
| 460(50) ms
| 5/2-#
|
|
|-
| style="text-indent:1em" | <sup>59m</sup>Cr
| colspan="3" style="text-indent:2em" | 503.0(17) keV
| 96(20) µs
| (9/2+)
|
|
|-
| <sup>60</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 36
| 59.95008(23)
| 560(60) ms
| 0+
|
|
|-
| <sup>61</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 37
| 60.95472(27)
| 261(15) ms
| 5/2-#
|
|
|-
| <sup>62</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 38
| 61.95661(36)
| 199(9) ms
| 0+
|
|
|-
| <sup>63</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 39
| 62.96186(32)#
| 129(2) ms
| (1/2-)#
|
|
|-
| <sup>64</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 40
| 63.96441(43)#
| 43(1) ms
| 0+
|
|
|-
| <sup>65</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 41
| 64.97016(54)#
| 27(3) ms
| (1/2-)#
|
|
|-
| <sup>66</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 42
| 65.97338(64)#
| 10(6) ms
| 0+
|
|
|-
| <sup>67</sup>Cr
| style="text-align:right" | 24
| style="text-align:right" | 43
| 66.97955(75)#
| 10# ms [>300 ns]
| 1/2-#
|
|
|}
=== Notes ===
* Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
* Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.
== References ==
* Isotope masses from [http://www.nndc.bnl.gov/amdc/index.html Ame2003 Atomic Mass Evaluation] by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in ''Nuclear Physics'' A729 (2003).
* Isotopic compositions and standard atomic masses from [http://www.iupac.org/publications/pac/2003/7506/7506x0683.html Atomic weights of the elements. Review 2000 (IUPAC Technical Report)]. ''Pure Appl. Chem.'' Vol. 75, No. 6, pp. 683-800, (2003) and [http://www.iupac.org/news/archives/2005/atomic-weights_revised05.html Atomic Weights Revised (2005)].
* Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
** Audi, Bersillon, Blachot, Wapstra. [http://amdc.in2p3.fr/web/nubase_en.html The Nubase2003 evaluation of nuclear and decay properties], Nuc. Phys. A 729, pp. 3-128 (2003).
** National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the [http://www.nndc.bnl.gov/nudat2/ NuDat 2.1 database] (retrieved Sept. 2005).
** David R. Lide (ed.), Norman E. Holden in ''CRC Handbook of Chemistry and Physics, 85th Edition'', online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.
==External links==
*[http://ie.lbl.gov/education/parent/Cr_iso.htm Chromium isotopes data from ''The Berkeley Laboratory Isotopes Project's'']
{{Isotope nav | element=chromium | lighter=Isotopes of vanadium | heavier=Isotopes of manganese }}
[[Category:Isotopes|Chromium]]
[[Category:Chromium]]
[[zh:鉻的同位素]]