Isotopes of platinum

Naturally occurring platinum (₇₈Pt) consists of five stable isotopes (¹⁹²Pt, ¹⁹⁴Pt, ¹⁹⁵Pt, ¹⁹⁶Pt, ¹⁹⁸Pt) and one long-lived (half-life 4.83×10¹¹ years) radioisotope (¹⁹⁰Pt). There are also 34 known synthetic radioisotopes ranging from ¹⁶⁵Pt to ²⁰⁴Pt, and longest-lived of those is ¹⁹³Pt with a half-life of 50 years. All the others have half-lives under two weeks, most under a day. There are numerous metastable states, of which the most stable are ^193mPt and ^195mPt with half-lives 4.33 and 4.010 days, decaying to their ground states.

Isotopes of platinum (₇₈Pt)

Main isotopes[1] Decay abun­dance half-life (t1/2) mode pro­duct 190Pt 0.0120% 4.83×1011 y α 186Os 191Pt synth 2.83 d ε 191Ir 192Pt 0.782% stable 193Pt synth 50 y ε 193Ir 194Pt 32.9% stable 195Pt 33.8% stable 196Pt 25.2% stable 198Pt 7.36% stable
Standard atomic weight Ar°(Pt)
	195.084±0.009[2] 195.08±0.02 (abridged)[3]
view talk edit

Despite the obstacles to measurement with rare isotopes of rare elements, with a very slow decay, the ¹⁹⁰Pt/¹⁸⁶Os system has been used in isotope geology, though not directly for dating.^[4]

All isotopes of platinum are either radioactive or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. Platinum-195 is the most abundant isotope, making platinum one of the only three elements to have its most abundant isotope with an odd neutron number (the other two being beryllium and nitrogen); however, it is so only by a small margin, unlike the other two, and is more in the nature of a coincidence.

List of isotopes

Nuclide [n 1]	Z	N	Isotopic mass (Da)[5] [n 2][n 3]	Half-life[1] [n 4]	Decay mode[1] [n 5]	Daughter isotope [n 6][n 7]	Spin and parity[1] [n 8][n 9]	Natural abundance (mole fraction)
	Excitation energy[n 9]							Normal proportion[1]	Range of variation
165Pt	78	87	164.99966(43)#	370(180) μs	α	161Os	7/2−#
166Pt	78	88	165.99487(32)#	294(62) μs	α	162Os	0+
167Pt	78	89	166.99275(33)#	920(120) μs	α	163Os	7/2−#
168Pt	78	90	167.98818(16)	2.02(10) ms	α	164Os	0+
					β+ ?	168Ir
169Pt	78	91	168.98662(22)#	6.99(9) ms	α	165Os	(7/2−)
					β+ ?	169Ir
170Pt	78	92	169.982502(20)	13.93(16) ms	α	166Os	0+
					β+ ?	170Ir
171Pt	78	93	170.981249(87)	45.5(25) ms	α (86%)	167Os	7/2−
					β+ (14%)	171Ir
171mPt	412.6(10) keV			901(9) ns	IT	171Pt	13/2+
172Pt	78	94	171.977341(11)	97.6(13) ms	α (96%)	168Os	0+
					β+ (4%)	172Ir
173Pt	78	95	172.976450(68)	382(2) ms	α (86%)	169Os	(5/2−)
					β+ (14%)	173Ir
174Pt	78	96	173.972820(11)	862(8) ms	α (74.9%)	170Os	0+
					β+ (25.1%)	174Ir
175Pt	78	97	174.972401(20)	2.43(4) s	α (64%)	171Os	(7/2−)
					β+ (36%)	175Ir
176Pt	78	98	175.968938(14)	6.33(15) s	β+ (60%)	176Ir	0+
					α (40%)	172Os
177Pt	78	99	176.968470(16)	10.0(04) s	β+ (94.3%)	177Ir	5/2−
					α (5.7%)	173Os
177mPt	147.5(4) keV			2.35(4) μs	IT	177Pt	1/2−
178Pt	78	100	177.965649(11)	20.7(7) s	β+ (92.3%)	178Ir	0+
					α (7.7%)	174Os
179Pt	78	101	178.9653588(86)	21.2(4) s	β+ (99.76%)	179Ir	1/2−
					α (0.24%)	175Os
180Pt	78	102	179.963038(11)	56(3) s	β+ (99.48%)	180Ir	0+
					α (0.52%)	176Os
181Pt	78	103	180.963090(15)	52.0(22) s	β+ (99.93%)	181Ir	1/2−
					α (0.074%)	177Os
181mPt	116.65(8) keV			>300 ns	IT	181Pt	7/2−
182Pt	78	104	181.961172(14)	2.67(12) min	β+ (99.962%)	182Ir	0+
					α (0.038%)	178Os
183Pt	78	105	182.961596(15)	6.5(10) min	β+ (99.99%)	183Ir	1/2−
					α (0.0096%)	179Os
183m1Pt	34.74(7) keV			43(5) s	β+ (96.9%)	183Ir	7/2−
					IT (3.1%)	183Pt
					α ?	179Os
183m2Pt	195.90(10) keV			>150 ns	IT	183Pt	9/2+
184Pt	78	106	183.959922(16)	17.3(2) min	β+	184Ir	0+
					α (0.0017%)	180Os
184mPt	1840.3(8) keV			1.01(5) ms	IT	184Pt	8−
185Pt	78	107	184.960614(28)	70.9(24) min	β+	185Ir	9/2+
					α (0.0050%)	181Os
185m1Pt	103.41(5) keV			33.0(8) min	β+	185Ir	1/2−
185m2Pt	200.89(4) keV			728(20) ns	IT	185Pt	5/2−
186Pt	78	108	185.959351(23)	2.08(5) h	β+	186Ir	0+
					α (1.4×10−4%)	182Os
187Pt	78	109	186.960617(26)	2.35(3) h	β+	187Ir	3/2−
187mPt	174.38(22) keV			311(15) μs	IT	187Pt	11/2+
188Pt	78	110	187.9593975(57)	10.16(18) d	EC	188Ir	0+
					α (2.6×10−5%)	184Os
189Pt	78	111	188.960848(11)	10.87(12) h	β+	189Ir	3/2−
189m1Pt	172.79(6) keV			464(25) ns	IT	189Pt	9/2−
189m2Pt	191.6(4) keV			143(5) μs	IT	189Pt	(13/2+)
190Pt	78	112	189.95994982(71)	4.83(3)×1011 y	α[n 10]	186Os	0+	1.2(2)×10−4
191Pt	78	113	190.9616763(44)	2.83(2) d	EC	191Ir	3/2−
191m1Pt	100.663(20) keV			>1 μs	IT	191Pt	9/2−
191m2Pt	149.035(22) keV			95(5) μs	IT	191Pt	13/2+
192Pt	78	114	191.9610427(28)	Observationally Stable[n 11]			0+	0.00782(24)
192mPt	2172.37(13) keV			272(23) ns	IT	192Pt	10−
193Pt	78	115	192.9629845(15)	50(6) y	EC	193Ir	1/2−
193mPt	149.78(4) keV			4.33(3) d	IT	193Pt	13/2+
194Pt	78	116	193.96268350(53)	Observationally Stable[n 12]			0+	0.3286(41)
195Pt	78	117	194.96479433(54)	Observationally Stable[n 13]			1/2−	0.3378(24)
195mPt	259.077(23) keV			4.010(5) d	IT	195Pt	13/2+
196Pt	78	118	195.96495465(55)	Observationally Stable[n 14]			0+	0.2521(34)
197Pt	78	119	196.96734303(58)	19.8915(19) h	β−	197Au	1/2−
197mPt	399.59(20) keV			95.41(18) min	IT (96.7%)	197Pt	13/2+
					β− (3.3%)	197Au
198Pt	78	120	197.9678967(23)	Observationally Stable[n 15]			0+	0.0734(13)
199Pt	78	121	198.9705970(23)	30.80(21) min	β−	199Au	5/2−
199mPt	424(2) keV			13.48(16) s	IT	199Pt	13/2+
200Pt	78	122	199.971445(22)	12.6(3) h	β−	200Au	0+
201Pt	78	123	200.974513(54)	2.5(1) min	β−	201Au	(5/2−)
202Pt	78	124	201.975639(27)	44(15) h	β−	202Au	0+
202mPt	1788.5(4) keV			141(7) μs	IT	202Pt	(7−)
203Pt	78	125	202.97906(22)#	22(4) s	β−	203Au	(1/2−)
203m1Pt	1367(3)# keV			12(5) s	β−	203Au	13/2+#
					IT ?	203Pt
203m2Pt	1420(50)# keV			>100# ns	IT	203Pt	27/2−#
203m3Pt	2530(50)# keV			641(55) ns	IT	203Pt	33/2+#
204Pt	78	126	203.98108(22)#	10.3(14) s	β−	204Au	0+
204m1Pt	1995.1(07) keV			5.5(7) μs	IT	204Pt	(5−)
204m2Pt	2035(23) keV			55(3) μs	IT	204Pt	(7−)
204m3Pt	3193(23) keV			146(14) ns	IT	204Pt	(10+)
205Pt	78	127	204.98624(32)#	2# s	β− ?	205Au	9/2+#
206Pt	78	128	205.99008(32)#	500# ms	β− ?	206Au	0+
					β−n ?	205Au
207Pt	78	129	206.99556(43)#	600# ms	β− ?	207Au	9/2+#
					β−n ?	206Au
208Pt	78	130	207.99946(43)#	220# ms	β− ?	208Au	0+
					β−n ?	207Au
This table header & footer: view

1. ^mPt – Excited nuclear isomer.
2. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
3. # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
4. Bold half-life – nearly stable, half-life longer than age of universe.
5. Modes of decay:

   EC:	Electron capture
   IT:	Isomeric transition

6. Bold italics symbol as daughter – Daughter product is nearly stable.
7. Bold symbol as daughter – Daughter product is stable.
8. ( ) spin value – Indicates spin with weak assignment arguments.
9. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
10. Theorized to also undergo β⁺β⁺ decay to ¹⁹⁰Os
11. Believed to undergo α decay to ¹⁸⁸Os with a half-life over 6.0×10¹⁶ years
12. Believed to undergo α decay to ¹⁹⁰Os
13. Believed to undergo α decay to ¹⁹¹Os with a half-life over 6.3×10¹⁸ years
14. Believed to undergo α decay to ¹⁹²Os
15. Believed to undergo α decay to ¹⁹⁴Os or double β⁻ decay to ¹⁹⁸Hg with a half-life over 3.20×10¹⁴ years

See also

Daughter products other than platinum

• Isotopes of gold
• Isotopes of iridium
• Isotopes of osmium