Natural holmium

Holmium

Holmium is a chemical element with the symbol Ho and atomic number 67. Part of the lanthanide series, holmium is a rare earth element. Its oxide was first isolated from rare earth ores in 1878 and the element was named after the city of Stockholm....

(Ho) contains one stable

Stable isotope

Stable isotopes are chemical isotopes that may or may not be radioactive, but if radioactive, have half-lives too long to be measured.Only 90 nuclides from the first 40 elements are energetically stable to any kind of decay save proton decay, in theory...

 isotope

Isotope

Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...

, ¹⁶⁵Ho. A number of synthetic radioactive isotopes are known, the most stable one is ¹⁶³Ho, with a half-life of 4,570 years. All other radioisotopes have half-lives not greater than 1.117 days in their ground states (although the metastable ^166mHo has a half-life of about 1,200 years), and most have half-lives under 3 hours.

Standard atomic mass: 164.93032(2) u

Table

nuclide symbol	Z(p Proton The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number.... )	N(n Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... )	isotopic mass (u)	half-life	decay mode(s)Abbreviations: EC: Electron capture Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino... IT: Isomeric transition Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer....	daughter isotope(s)Bold for stable isotopes	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
	excitation energy
140Ho	67	73	139.96854(54)#	6(3) ms			8+#
141Ho	67	74	140.96310(54)#	4.1(3) ms			(7/2-)
141mHo	66(2) keV			6.4(8) µs			(1/2+)
142Ho	67	75	141.95977(54)#	400(100) ms	β+ Beta decay In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a...	142Dy	(6 to 9)
					p Proton emission Proton emission is a type of radioactive decay in which a proton is ejected from a nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay, in which case the process is known as beta-delayed proton emission, or can occur from the ground state of very...	141Dy
143Ho	67	76	142.95461(43)#	300# ms [>200 ns]	β+	143Dy	11/2-#
144Ho	67	77	143.95148(32)#	0.7(1) s	β+	144Dy
					β+, p	143Tb
145Ho	67	78	144.94720(32)#	2.4(1) s	β+	145Dy	(11/2-)
145mHo	100(100)# keV			100# ms			5/2+#
146Ho	67	79	145.94464(21)#	3.6(3) s	β+	146Dy	(10+)
					β+, p (rare)	145Tb
147Ho	67	80	146.94006(3)	5.8(4) s	β+	147Dy	(11/2-)
					β+, p (rare)	146Tb
148Ho	67	81	147.93772(14)	2.2(11) s	β+	148Dy	(1+)
148m1Ho	400(100)# keV			9.49(12) s	β+ (99.92%)	148Dy	(6)-
					β+, p (.08%)	147Tb
148m2Ho	690(100)# keV			2.35(4) ms			(10+)
149Ho	67	82	148.933775(20)	21.1(2) s	β+	149Dy	(11/2-)
149m1Ho	48.80(20) keV			56(3) s	β+	149Dy	(1/2+)
149m2Ho	7200(350) keV			>=100 ns
150Ho	67	83	149.933496(15)	76.8(18) s	β+	150Dy	2-
150m1Ho	-10(50) keV			23.3(3) s	β+	150Dy	(9)+
150m2Ho	~8000 keV			751 ns
151Ho	67	84	150.931688(13)	35.2(1) s	β+ (78%)	151Dy	11/2(-)
					α Alpha decay Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less...  (22%)	147Tb
151mHo	41.0(2) keV			47.2(10) s	α (77%)	147Tb	1/2(+)
					β+ (22%)	151Dy
152Ho	67	85	151.931714(15)	161.8(3) s	β+ (88%)	152Dy	2-
					α (12%)	148Tb
152m1Ho	160(1) keV			50.0(4) s			9+
152m2Ho	3019.59(19) keV			8.4(3) µs			19-
153Ho	67	86	152.930199(6)	2.01(3) min	β+ (99.94%)	153Dy	11/2-
					α (.05%)	149Tb
153m1Ho	68.7(3) keV			9.3(5) min	β+ (99.82%)	153Dy	1/2+
					α (.18%)	149Tb
153m2Ho	2772 keV			229(2) ns			(31/2+)
154Ho	67	87	153.930602(9)	11.76(19) min	β+ (99.98%)	154Dy	2-
					α (.02%)	150Tb
154mHo	238(30) keV			3.10(14) min	β+ (99.99%)	154Dy	8+
					α (.001%)	150Tb
					IT Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer....  (rare)	154Ho
155Ho	67	88	154.929103(19)	48(1) min	β+	155Dy	5/2+
155mHo	141.97(11) keV			880(80) µs			11/2-
156Ho	67	89	155.92984(5)	56(1) min	β+	156Dy	4-
156m1Ho	100(50)# keV			7.8(3) min	β+	156Dy	(9+)
					IT	156Ho
156m2Ho	52.4(5) keV			9.5(15) s			1-
157Ho	67	90	156.928256(26)	12.6(2) min	β+	157Dy	7/2-
158Ho	67	91	157.928941(29)	11.3(4) min	β+ (93%)	158Dy	5+
					α (7%)	154Tb
158m1Ho	67.200(10) keV			28(2) min	IT (81%)	158Ho	2-
					β+ (19%)	158Dy
158m2Ho	180(70)# keV			21.3(23) min			(9+)
159Ho	67	92	158.927712(4)	33.05(11) min	β+	159Dy	7/2-
159mHo	205.91(5) keV			8.30(8) s	IT	159Ho	1/2+
160Ho	67	93	159.928729(16)	25.6(3) min	β+	160Dy	5+
160m1Ho	59.98(3) keV			5.02(5) h	IT (65%)	160Ho	2-
					β+ (35%)	160Dy
160m2Ho	197(16) keV			3 s			(9+)
161Ho	67	94	160.927855(3)	2.48(5) h	EC Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...	161Dy	7/2-
161mHo	211.16(3) keV			6.76(7) s	IT	161Ho	1/2+
162Ho	67	95	161.929096(4)	15.0(10) min	β+	162Dy	1+
162mHo	106(7) keV			67.0(7) min	IT (62%)	162Ho	6-
					β+ (38%)	162Dy
163Ho	67	96	162.9287339(27)	4570(25) a	EC	163Dy	7/2-
163mHo	297.88(7) keV			1.09(3) s	IT	163Ho	1/2+
164Ho	67	97	163.9302335(30)	29(1) min	EC (60%)	164Dy	1+
					β- (40%)	164Er
164mHo	139.77(8) keV			38.0(10) min [37.5(+15-5) min]	IT	164Ho	6-
165Ho	67	98	164.9303221(27)	Observationally StableBelieved to undergo α decay to 161Tb			7/2-	1.0000
166Ho	67	99	165.9322842(27)	26.83(2) h	β-	166Er	0-
166m1Ho	5.985(18) keV			1,200(180) a	β-	166Er	(7)-
166m2Ho	190.9052(20) keV			185(15) µs			3+
167Ho	67	100	166.933133(6)	3.003(18) h	β-	167Er	7/2-
167mHo	259.34(11) keV			6.0(10) µs			3/2+
168Ho	67	101	167.93552(3)	2.99(7) min	β-	168Er	3+
168m1Ho	59(1) keV			132(4) s	IT (99.5%)	168Ho	(6+)
					β- (.5%)	168Er
168m2Ho	143.4(2) keV			>4 µs			(1)-
168m3Ho	192.6(2) keV			108(11) ns			1+
169Ho	67	102	168.936872(22)	4.72(10) min	β-	169Er	7/2-
170Ho	67	103	169.93962(5)	2.76(5) min	β-	170Er	6+#
170mHo	120(70) keV			43(2) s	β-	170Er	(1+)
171Ho	67	104	170.94147(64)	53(2) s	β-	171Er	7/2-#
172Ho	67	105	171.94482(43)#	25(3) s	β-	172Er
173Ho	67	106	172.94729(43)#	10# s	β-	173Er	7/2-#
174Ho	67	107	173.95115(54)#	8# s
175Ho	67	108	174.95405(64)#	5# s			7/2-#

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