Isotopes of silver

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Naturally occurring silver (Ag) is composed of the two stable isotopes ¹⁰⁷Ag and ¹⁰⁹Ag with ¹⁰⁷Ag being the more abundant (51.839% natural abundance). Standard atomic mass: 107.8682(2) u. Twenty-eight radioisotopes have been characterised with the most stable being ¹⁰⁵Ag with a half-life of 41.29 days, ¹¹¹Ag with a half-life of 7.45 days, and ¹¹²Ag with a half-life of 3.13 hours.

All of the remaining radioactive isotopes have half-lives that are less than an hour and the majority of these have half-lives that are less than 3 minutes. This element has numerous meta states with the most stable being ^108mAg (t_* 418 years), ^110mAg (t_* 249.79 days) and ^106mAg (t_* 8.28 days).

Isotopes of silver range in atomic weight from 93.943 u (⁹⁴Ag) to 123.929 u (¹²⁴Ag). The primary decay mode before the most abundant stable isotope, ¹⁰⁷Ag, is electron capture and the primary mode after is beta decay. The primary decay products before ¹⁰⁷Ag are palladium (element 46) isotopes and the primary products after are cadmium (element 48) isotopes.

The palladium isotope ¹⁰⁷Pd decays by beta emission to ¹⁰⁷Ag with a half-life of 6.5 million years. Iron meteorites are the only objects with a high enough palladium/silver ratio to yield measurable variations in ¹⁰⁷Ag abundance. Radiogenic ¹⁰⁷Ag was first discovered in the Santa Clara meteorite in 1978.

The discoverers suggest that the coalescence and differentiation of iron-cored small planets may have occurred 10 million years after a nucleosynthetic event. ¹⁰⁷Pd versus Ag correlations observed in bodies, which have clearly been melted since the accretion of the solar system, must reflect the presence of live short-lived nuclides in the early solar system.
Standard atomic mass: 107.8682(2) u

[edit] Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
nuclide symbol	excitation energy			half-life	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
⁹³Ag	47	46	92.94978(64)#	5# ms [>1.5 µs]	9/2+#
⁹⁴Ag	47	47	93.94278(54)#	37(18) ms [26(+26-9) ms]	0+#
^94m1Ag	1350(400)# keV			422(16) ms	(7+)
^94m2Ag	6500(2000)# keV			300(200) ms	(21+)
⁹⁵Ag	47	48	94.93548(43)#	1.74(13) s	(9/2+)
^95m1Ag	344.2(3) keV			<0.5 s	(1/2-)
^95m2Ag	2531(1) keV			<16 ms	(23/2+)
^95m3Ag	4859(1) keV			<40 ms	(37/2+)
⁹⁶Ag	47	49	95.93068(43)#	4.45(4) s	(8+)
^96m1Ag	0(50)# keV			6.9(6) s	(2+)
^96m2Ag				700(200) ns
⁹⁷Ag	47	50	96.92397(35)	25.3(3) s	(9/2+)
^97mAg	2343(49) keV			5 ns	(21/2+)
⁹⁸Ag	47	51	97.92157(7)	47.5(3) s	(5+)
^98mAg	167.83(15) keV			220(20) ns	(3+)
⁹⁹Ag	47	52	98.91760(16)	124(3) s	(9/2)+
^99mAg	506.1(4) keV			10.5(5) s	(1/2-)
¹⁰⁰Ag	47	53	99.91610(8)	2.01(9) min	(5)+
^100mAg	15.52(16) keV			2.24(13) min	(2)+
¹⁰¹Ag	47	54	100.91280(11)	11.1(3) min	9/2+
^101mAg	274.1(3) keV			3.10(10) s	1/2-
¹⁰²Ag	47	55	101.91169(3)	12.9(3) min	5+
^102mAg	9.3(4) keV			7.7(5) min	2+
¹⁰³Ag	47	56	102.908973(18)	65.7(7) min	7/2+
^103mAg	134.45(4) keV			5.7(3) s	1/2-
¹⁰⁴Ag	47	57	103.908629(6)	69.2(10) min	5+
^104mAg	6.9(4) keV			33.5(20) min	2+
¹⁰⁵Ag	47	58	104.906529(12)	41.29(7) d	1/2-
^105mAg	25.465(12) keV			7.23(16) min	7/2+
¹⁰⁶Ag	47	59	105.906669(5)	23.96(4) min	1+
^106mAg	89.66(7) keV			8.28(2) d	6+
¹⁰⁷Ag	47	60	106.905097(5)	STABLE	1/2-	0.51839(8)
^107mAg	93.125(19) keV			44.3(2) s	7/2+
¹⁰⁸Ag	47	61	107.905956(5)	2.37(1) min	1+
^108mAg	109.440(7) keV			418(21) a	6+
¹⁰⁹Ag	47	62	108.904752(3)	STABLE	1/2-	0.48161(8)
^109mAg	88.0341(11) keV			39.6(2) s	7/2+
¹¹⁰Ag	47	63	109.906107(3)	24.6(2) s	1+
^110m1Ag	1.113 keV			660(40) ns	2-
^110m2Ag	117.59(5) keV			249.950(24) d	6+
¹¹¹Ag	47	64	110.905291(3)	7.45(1) d	1/2-
^111mAg	59.82(4) keV			64.8(8) s	7/2+
¹¹²Ag	47	65	111.907005(18)	3.130(9) h	2(-)
¹¹³Ag	47	66	112.906567(18)	5.37(5) h	1/2-
^113mAg	43.50(10) keV			68.7(16) s	7/2+
¹¹⁴Ag	47	67	113.908804(27)	4.6(1) s	1+
^114mAg	199(5) keV			1.50(5) ms	(<7+)
¹¹⁵Ag	47	68	114.90876(4)	20.0(5) min	1/2-
^115mAg	41.16(10) keV			18.0(7) s	7/2+
¹¹⁶Ag	47	69	115.91136(5)	2.68(10) min	(2)-
^116mAg	81.90(20) keV			8.6(3) s	(5+)
¹¹⁷Ag	47	70	116.91168(5)	73.6(14) s [72.8(+20-7) s]	1/2-#
^117mAg	28.6(2) keV			5.34(5) s	(7/2+)
¹¹⁸Ag	47	71	117.91458(7)	3.76(15) s	1-
^118m1Ag	45.79(9) keV			~0.1 µs	0(-) to 2(-)
^118m2Ag	127.49(5) keV			2.0(2) s	4(+)
^118m3Ag	279.37(20) keV			~0.1 µs	(2+,3+)
¹¹⁹Ag	47	72	118.91567(10)	6.0(5) s	1/2-#
^119mAg	20(20)# keV			2.1(1) s	7/2+#
¹²⁰Ag	47	73	119.91879(8)	1.23(4) s	3(+#)
^120mAg	203.0(10) keV			371(24) ms	6(-)
¹²¹Ag	47	74	120.91985(16)	0.79(2) s	(7/2+)#
¹²²Ag	47	75	121.92353(22)#	0.529(13) s	(3+)
^122mAg	80(50)# keV			1.5(5) s	8-#
¹²³Ag	47	76	122.92490(22)#	0.300(5) s	(7/2+)
¹²⁴Ag	47	77	123.92864(21)#	172(5) ms	3+#
^124mAg	0(100)# keV			200# ms	8-#
¹²⁵Ag	47	78	124.93043(32)#	166(7) ms	(7/2+)#
¹²⁶Ag	47	79	125.93450(32)#	107(12) ms	3+#
¹²⁷Ag	47	80	126.93677(32)#	79(3) ms	7/2+#
¹²⁸Ag	47	81	127.94117(32)#	58(5) ms
¹²⁹Ag	47	82	128.94369(43)#	44(7) ms [46(+5-9) ms]	7/2+#
^129mAg	0(200)# keV			~160 ms	1/2-#
¹³⁰Ag	47	83	129.95045(36)#	~50 ms	0+

[edit] Notes

The precision of the isotope abundances and atomic mass is limited through variations. The given ranges should be applicable to any normal terrestrial material.
Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.
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.

[edit] References

Isotope masses from 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 Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and 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. 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 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.