Isotopes of phosphorus

Although phosphorus (P) has 23 isotopes from ²⁴P to ⁴⁶P, only one of these isotopes is stable ³¹P; as such, it is considered a monoisotopic element. The longest-lived radioactive isotopes are ³³P with a half-life of 25.34 days and ³²P with a half-life of 14.263 days. All other have half-lives under 2.5 minutes, most under a second. The least stable is ²⁵P with a half-life shorter than 30 nanoseconds—the half-life of ²⁴P is unknown.

Relative atomic mass: 30.973762(2)

Radioactive isotopes of phosphorus include:

• ³²P, a beta-emitter (1.71 MeV) with a half-life of 14.3 days, is used routinely in life-science laboratories, primarily to produce radiolabeled DNA and RNA probe, e.g. for use in Northern blots or Southern blots. Because the high-energy beta particles produced penetrate skin and corneas, and because any ³²P ingested, inhaled, or absorbed is readily incorporated into bone and nucleic acids, OSHA requires that a lab coat, disposable gloves, and safety glasses or goggles be worn when working with ³²P, and that working directly over an open container be avoided in order to protect the eyes. Monitoring personal, clothing, and surface contamination is also required. In addition, due to the high energy of the beta particles, shielding this radiation with the normally used dense materials (e.g. lead), gives rise to secondary emission of X-rays via a process known as bremsstrahlung, meaning braking radiation. Therefore shielding must be accomplished with low-density materials, e.g. Plexiglas, Lucite, plastic, wood, or water.
• ³³P, a beta-emitter (0.25 MeV) with a half-life of 25.4 days. It is used in life-science laboratories in applications in which lower energy beta emissions are advantageous such as DNA sequencing. Phosphorus-33 can be used to label nucleotides. It is less energetic than ³²P, giving a better resolution. A disadvantage is its higher cost compared to ³²P, as most of the bombarded ³¹P will have acquired only one neutron, while only some will have acquired two or more. Its maximum specific activity is 5118 Ci/mol.

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)[1]	daughter isotope(s)[n 1]	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
^24P	15	9	24.03435(54)#	?	p (>99.9%)	^23Si	(1+)#
					β^+ (<.1%)	^24Si
^25P	15	10	25.02026(21)#	<30 ns	p	^24Si	(1/2+)#
^26P[n 2]	15	11	26.01178(21)#	43.7(6) ms	β^+ (98.1%)	^26Si	(3+)
					β^+, 2p (1.0%)	^24Mg
					β^+, p (.9%)	^25Al
^27P	15	12	26.999230(28)	260(80) ms	β^+ (99.93%)	^27Si	1/2+
					β^+, p (.07%)	^26Al
^28P	15	13	27.992315(4)	270.3(5) ms	β^+ (99.99%)	^28Si	3+
					β^+, p (.0013%)	^27Al
					β^+, α (8.6×10^−4%)	^24Mg
^29P	15	14	28.9818006(6)	4.142(15) s	β^+	^29Si	1/2+
^30P	15	15	29.9783138(3)	2.498(4) min	β^+	^30Si	1+
^31P	15	16	30.97376163(20)	Stable			1/2+	1.0000
^32P	15	17	31.97390727(20)	14.263(3) d	β^−	^32S	1+	trace
^33P	15	18	32.9717255(12)	25.34(12) d	β^−	^33S	1/2+
^34P	15	19	33.973636(5)	12.43(8) s	β^−	^34S	1+
^35P	15	20	34.9733141(20)	47.3(7) s	β^−	^35S	1/2+
^36P	15	21	35.978260(14)	5.6(3) s	β^−	^36S	4−#
^37P	15	22	36.97961(4)	2.31(13) s	β^−	^37S	1/2+#
^38P	15	23	37.98416(11)	0.64(14) s	β^− (88%)	^38S
					β^−, n (12%)	^37S
^39P	15	24	38.98618(11)	190(50) ms	β^− (74%)	^39S	1/2+#
					β^−, n (26%)	^38S
^40P	15	25	39.99130(15)	153(8) ms	β^− (70%)	^40S	(2−,3−)
					β^−, n (30%)	^39S
^41P	15	26	40.99434(23)	100(5) ms	β^− (70%)	^41S	1/2+#
					β^−, n (30%)	^40S
^42P	15	27	42.00101(48)	48.5(15) ms	β^− (50%)	^42S
					β^−, n (50%)	^41S
^43P	15	28	43.00619(104)	36.5(15) ms	β^−, n	^42S	1/2+#
^44P	15	29	44.01299(75)#	18.5(25) ms	β^−	^44S
^45P	15	30	45.01922(86)#	8# ms [>200 ns]	β^−	^45S	1/2+#
^46P	15	31	46.02738(97)#	4# ms [>200 ns]	β^−	^46S

1. Bold for stable isotopes
2. Has 1 halo proton

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:
  • G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
• Isotopic compositions and standard atomic masses from:
  • J. R. de Laeter; J. K. Böhlke; P. De Bièvre; H. Hidaka; H. S. Peiser; K. J. R. Rosman; P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683.
  • M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary.
• Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
  • G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
  • National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005.
  • N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.

External links

• Phosphorus isotopes data from The Berkeley Laboratory Isotopes Project's

1. "Universal Nuclide Chart". nucleonica. (registration required (help)).