Erbium-168

Properties and data of the isotope ¹⁶⁸Er.

Content

General data

Name of the isotope:Erbium-168; Er-168Symbol:¹⁶⁸Er or 16868ErMass number A:168 (= number of nucleons)Atomic number Z:68 (= number of protons)Neutrons N:100Isotopic mass:167.93238(2) u (atomic weight of Erbium-168)Nuclide mass:167.8950799 u (calculated nuclear mass without electrons)Mass excess:-62.98762 MeVMass defect:1.466213776 u (per nucleus)Nuclear binding energy:1365.76933506 MeV (per nucleus)
8.12957938 MeV (average binding energy per nucleon)Separation energy:S_N = 7.77131(12) MeV (first neutron)
S_P = 8.000(5) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)0+Charge radius:5.2644(35) femtometer fmYear of discovery:1934

Parent Nuclides

Direct parent isotopes are: ¹⁶⁸Tm, ¹⁶⁸Ho.

Occurrence

Comparison of the natural Erbium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Erbium Isotopic mixture	167.259 u	100 %
Isotope ¹⁶²Er	161.92879(2) u	0.139(5) %	stable	0+
Isotope ¹⁶⁴Er	163.92921(2) u	1.601(3) %	stable	0+
Isotope ¹⁶⁶Er	165.93030(2) u	33.503(36) %	stable	0+
Isotope ¹⁶⁷Er	166.93205(2) u	22.869(9) %	stable	7/2+
Isotope ¹⁶⁸Er	167.93238(2) u	26.978(18) %	stable	0+
Isotope ¹⁷⁰Er	169.93547(2) u	14.910(36) %	stable	0+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 100) and isobaric (same nucleon number A = 168) with Erbium-168. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 100	Isobar A = 168
59	¹⁵⁹Pr
60	¹⁶⁰Nd
61	¹⁶¹Pm
62	¹⁶²Sm
63	¹⁶³Eu	¹⁶⁸Eu
64	¹⁶⁴Gd	¹⁶⁸Gd
65	¹⁶⁵Tb	¹⁶⁸Tb
66	¹⁶⁶Dy	¹⁶⁸Dy
67	¹⁶⁷Ho	¹⁶⁸Ho
68	¹⁶⁸Er	¹⁶⁸Er
69	¹⁶⁹Tm	¹⁶⁸Tm
70	¹⁷⁰Yb	¹⁶⁸Yb
71	¹⁷¹Lu	¹⁶⁸Lu
72	¹⁷²Hf	¹⁶⁸Hf
73	¹⁷³Ta	¹⁶⁸Ta
74	¹⁷⁴W	¹⁶⁸W
75	¹⁷⁵Re	¹⁶⁸Re
76	¹⁷⁶Os	¹⁶⁸Os
77	¹⁷⁷Ir	¹⁶⁸Ir
78	¹⁷⁸Pt	¹⁶⁸Pt
79	¹⁷⁹Au
80	¹⁸⁰Hg
81	¹⁸¹Tl
82	¹⁸²Pb