Erbij[um] (Er)

hemijski element sa simbolom Er i atomskim brojem 68

Atomic Number	68
Atomic Weight	167.259
Maseni broj	166

Group
Period	6
Block	f

Proton	68 p⁺
Neutron	98 n⁰
Elektron	68 e^-

Animated Bohrov model atoma of Er (Erbij[um])

Physical Property

Atomski Radijus	175 pm 272 pm
Molarni volumen	18,4 cm³/mol
covalent radius	165 pm 133 pm 189 pm
Metallic Radius
Ionski radijus	89 pm 94,5 pm 100,4 pm 106,2 pm
Crystal Radius	103 pm 108,5 pm 114,4 pm 120,2 pm
Van der Waalsov radijus	229 pm 267 pm 339,1 pm
gustoća	9,07 g/cm³ 8.860 kg/m³

Chemical Property

{ERROR}

energija

proton affinity
electron affinity
ionization energy	6,1077 eV/particle 11,93 eV/particle 22,74 eV/particle 42,7 eV/particle 65,1 eV/particle 96 eV/particle 114 eV/particle 131 eV/particle 158 eV/particle 177 eV/particle 201 eV/particle 235 eV/particle 268 eV/particle 290 eV/particle 311 eV/particle 345 eV/particle 381 eV/particle 415 eV/particle 450 eV/particle 486 eV/particle 520 eV/particle 555 eV/particle 770 eV/particle 810 eV/particle 853 eV/particle 899 eV/particle 943 eV/particle 989 eV/particle 1.046 eV/particle 1.092 eV/particle 1.142 eV/particle 1.188 eV/particle 1.370 eV/particle 1.416 eV/particle 1.468 eV/particle 1.516 eV/particle 1.625 eV/particle 1.678 eV/particle 1.803 eV/particle 1.859 eV/particle 3.157 eV/particle 3.265 eV/particle 3.381 eV/particle 3.505 eV/particle 3.624 eV/particle 3.742 eV/particle 3.916 eV/particle 4.038 eV/particle 4.170 eV/particle 4.294 eV/particle 4.639 eV/particle 4.748 eV/particle 4.866 eV/particle 4.978 eV/particle 5.329 eV/particle 5.455 eV/particle 5.695 eV/particle 5.815 eV/particle 12.918 eV/particle 13.217 eV/particle 13.548 eV/particle 13.855 eV/particle 15.146 eV/particle 15.511 eV/particle 15.971 eV/particle 16.274,56 eV/particle 65.848,24 eV/particle 67.241,85 eV/particle

Toplota isparavanja	317 kJ/mol
toplota topljenja
standard enthalpy of formation	316,4 kJ/mol
Elektron

electron shell	2, 8, 18, 30, 8, 2

Valentni elektron	2 ⓘ

electron configuration	[Xe] 4f¹² 6s²ⓘ 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 4f¹² 6s²

oksidacijsko stanje	0, 2, 3
Elektronegativnost	0.212261 1.24
Electrophilicity Index
fundamental state of matter

agregatno stanje
gaseous state of matter
Boiling Point	3.141,15 K
Melting Point	1.802,15 K
critical pressure
Kritična temperatura
Trojna tačka
appearance
boja	Black #ff1493 #00e675 #00e675
appearance	silvery white
Indeks prelamanja
thermodynamic material property
Thermal Conductivity
thermal expansion	0,0000122 1/K
molar heat capacity	28,12 J/(mol K)
Specific Heat Capacity	0,168 J/(g⋅K)
heat capacity ratio
electrical properties
type	Conductor
Specifična električna provodljivost	1,2 MS/m
electrical resistivity	0,00000086 Ω*m
Superprovodljivost
Magnetizam
type	paramagnetic
magnetic susceptibility (Mass)	0,00000377 m³/Kg
magnetic susceptibility (Molar)	0,000000630566 m³/mol
magnetic susceptibility (Volume)	0,0341788
magnetic ordering
Kirijeva tačka	32 K
Néel temperature	82 K
struktura
Crystal Structure	{ERROR}
lattice constant	3,56 Å
Lattice Angles	π/2, π/2, 2 π/3
mechanical property
Tvrdoća	814 MPa 589 MPa
bulk modulus	44 GPa
shear modulus	28 GPa
Young's modulus	70 GPa
Poisson's ratio	0,24
Brzina zvuka	2.830 m/s
klasifikacija
Category	Actinides, Lanthanides
CAS Group
IUPAC Group
Glawe Number	22
Mendeleev Number	35
Pettifor Number	23
Geochemical Class	rare earth & related
Goldschmidt classification	litophile

other

Gas Basicity
polarizability	150 ± 10 a₀
C6 Dispersion Coefficient	2.150 a₀
allotrope
Neutron cross section	165
Neutron Mass Absorption	0,036
Kvantni brojevi	3H6
space group	194 (P63/mmc)

Isotopes of Erbium

Stable Isotopes	3
Unstable Isotopes	36
Natural Isotopes	6

¹⁴²Er

Maseni broj	142
broj neutrona	74
Relative Atomic Mass	141,970016 ± 0,000537 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada
spin	0
nuclear quadrupole moment	0
datum otkrića
parity	+

decay mode	intensity
p (proton emission)

¹⁴³Er

Maseni broj	143
broj neutrona	75
Relative Atomic Mass	142,966548 ± 0,000429 Da
g-factor
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada
spin	9/2
nuclear quadrupole moment
datum otkrića	2005
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)
β⁺ p (β⁺-delayed proton emission)

¹⁴⁴Er

Maseni broj	144
broj neutrona	76
Relative Atomic Mass	143,9607 ± 0,00021 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada
spin	0
nuclear quadrupole moment	0
datum otkrića	2003
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)

¹⁴⁵Er

Maseni broj	145
broj neutrona	77
Relative Atomic Mass	144,957874 ± 0,000215 Da
g-factor
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	900 ± 200 ms
spin	1/2
nuclear quadrupole moment	0
datum otkrića	1989
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)

¹⁴⁶Er

Maseni broj	146
broj neutrona	78
Relative Atomic Mass	145,952418357 ± 0,000007197 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	1,7 ± 0,6 s
spin	0
nuclear quadrupole moment	0
datum otkrića	1993
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)

¹⁴⁷Er

Maseni broj	147
broj neutrona	79
Relative Atomic Mass	146,949964456 ± 0,000041 Da
g-factor
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	3,2 ± 1,2 s
spin	1/2
nuclear quadrupole moment	0
datum otkrića	1992
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)

¹⁴⁸Er

Maseni broj	148
broj neutrona	80
Relative Atomic Mass	147,944735026 ± 0,000011 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	4,6 ± 0,2 s
spin	0
nuclear quadrupole moment	0
datum otkrića	1982
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)	0.15%

¹⁴⁹Er

Maseni broj	149
broj neutrona	81
Relative Atomic Mass	148,942306 ± 0,00003 Da
g-factor
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	4 ± 2 s
spin	1/2
nuclear quadrupole moment	0
datum otkrića	1984
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
β⁺ p (β⁺-delayed proton emission)	7%

¹⁵⁰Er

Maseni broj	150
broj neutrona	82
Relative Atomic Mass	149,937915524 ± 0,000018458 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	18,5 ± 0,7 s
spin	0
nuclear quadrupole moment	0
datum otkrića	1982
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%

¹⁵¹Er

Maseni broj	151
broj neutrona	83
Relative Atomic Mass	150,937448567 ± 0,000017681 Da
g-factor
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	23,5 ± 2 s
spin	7/2
nuclear quadrupole moment
datum otkrića	1970
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%

¹⁵²Er

Maseni broj	152
broj neutrona	84
Relative Atomic Mass	151,935050347 ± 0,000009478 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	10,3 ± 0,1 s
spin	0
nuclear quadrupole moment	0
datum otkrića	1963
parity	+

decay mode	intensity
α (α emission)	90%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	10%

¹⁵³Er

Maseni broj	153
broj neutrona	85
Relative Atomic Mass	152,93508635 ± 0,000009967 Da
g-factor	-0,26628571428571 ± 0,002
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	37,1 ± 0,2 s
spin	7/2
nuclear quadrupole moment	-0,42 ± 0,02
datum otkrića	1963
parity	-

decay mode	intensity
α (α emission)	53%
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	47%

¹⁵⁴Er

Maseni broj	154
broj neutrona	86
Relative Atomic Mass	153,932790799 ± 0,000005325 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	3,73 ± 0,09 m
spin	0
nuclear quadrupole moment	0
datum otkrića	1963
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
α (α emission)	0.47%

¹⁵⁵Er

Maseni broj	155
broj neutrona	87
Relative Atomic Mass	154,93321571 ± 0,00000652 Da
g-factor	-0,19028571428571 ± 0,0014285714285714
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	5,3 ± 0,3 m
spin	7/2
nuclear quadrupole moment	-0,27 ± 0,02
datum otkrića	1969
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	99.978%
α (α emission)	0.022%

¹⁵⁶Er

Maseni broj	156
broj neutrona	88
Relative Atomic Mass	155,931065926 ± 0,00002644 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	19,5 ± 1 m
spin	0
nuclear quadrupole moment	0
datum otkrića	1967
parity	+

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%
α (α emission)	1.2%

¹⁵⁷Er

Maseni broj	157
broj neutrona	89
Relative Atomic Mass	156,931922652 ± 0,000028454 Da
g-factor	-0,274 ± 0,002
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	18,65 ± 0,1 m
spin	3/2
nuclear quadrupole moment	0,92 ± 0,01
datum otkrića	1966
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%

¹⁵⁸Er

Maseni broj	158
broj neutrona	90
Relative Atomic Mass	157,929893474 ± 0,000027074 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	2,29 ± 0,06 h
spin	0
nuclear quadrupole moment	0
datum otkrića	1961
parity	+

decay mode	intensity
ϵ (electron capture)	100%

¹⁵⁹Er

Maseni broj	159
broj neutrona	91
Relative Atomic Mass	158,93069079 ± 0,00000391 Da
g-factor	-0,202 ± 0,0013333333333333
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	36 ± 1 m
spin	3/2
nuclear quadrupole moment	1,17 ± 0,01
datum otkrića	1962
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%

¹⁶⁰Er

Maseni broj	160
broj neutrona	92
Relative Atomic Mass	159,929077193 ± 0,000026029 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	28,58 ± 0,09 h
spin	0
nuclear quadrupole moment	0
datum otkrića	1954
parity	+

decay mode	intensity
ϵ (electron capture)	100%

¹⁶¹Er

Maseni broj	161
broj neutrona	93
Relative Atomic Mass	160,93000353 ± 0,000009419 Da
g-factor	-0,24266666666667 ± 0,002
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	3,21 ± 0,03 h
spin	3/2
nuclear quadrupole moment	1,363 ± 0,008
datum otkrića	1954
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%

¹⁶²Er

Maseni broj	162
broj neutrona	94
Relative Atomic Mass	161,928787299 ± 0,000000811 Da
g-factor	0
natural abundance	0,139 ± 0,005
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada
spin	0
nuclear quadrupole moment	0
datum otkrića	1938
parity	+

decay mode	intensity
α (α emission)
2β⁺ (double β⁺ decay)

¹⁶³Er

Maseni broj	163
broj neutrona	95
Relative Atomic Mass	162,930039908 ± 0,000004967 Da
g-factor	0,2224 ± 0,0016
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	75 ± 0,4 m
spin	5/2
nuclear quadrupole moment	2,56 ± 0,02
datum otkrića	1953
parity	-

decay mode	intensity
β⁺ (β⁺ decay; β⁺ = ϵ + e⁺)	100%

¹⁶⁴Er

Maseni broj	164
broj neutrona	96
Relative Atomic Mass	163,929207739 ± 0,000000755 Da
g-factor	0
natural abundance	1,601 ± 0,003
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada
spin	0
nuclear quadrupole moment	0
datum otkrića	1938
parity	+

decay mode	intensity
α (α emission)
2β⁺ (double β⁺ decay)

¹⁶⁵Er

Maseni broj	165
broj neutrona	97
Relative Atomic Mass	164,930733482 ± 0,000000985 Da
g-factor	0,2564 ± 0,0016
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	10,36 ± 0,04 h
spin	5/2
nuclear quadrupole moment	2,71 ± 0,03
datum otkrića	1950
parity	-

decay mode	intensity
ϵ (electron capture)	100%

¹⁶⁶Er

Maseni broj	166
broj neutrona	98
Relative Atomic Mass	165,930301067 ± 0,000000358 Da
g-factor	0
natural abundance	33,503 ± 0,036
Radioaktivnost	stable isotope
Vrijeme poluraspada	Not Radioactive ☢️
spin	0
nuclear quadrupole moment	0
datum otkrića	1934
parity	+

¹⁶⁷Er

Maseni broj	167
broj neutrona	99
Relative Atomic Mass	166,932056192 ± 0,000000306 Da
g-factor	-0,16065714285714 ± 0,00011428571428571
natural abundance	22,869 ± 0,009
Radioaktivnost	stable isotope
Vrijeme poluraspada	Not Radioactive ☢️
spin	7/2
nuclear quadrupole moment	3,57 ± 0,03
datum otkrića	1934
parity	+

¹⁶⁸Er

Maseni broj	168
broj neutrona	100
Relative Atomic Mass	167,932378282 ± 0,00000028 Da
g-factor	0
natural abundance	26,978 ± 0,018
Radioaktivnost	stable isotope
Vrijeme poluraspada	Not Radioactive ☢️
spin	0
nuclear quadrupole moment	0
datum otkrića	1934
parity	+

¹⁶⁹Er

Maseni broj	169
broj neutrona	101
Relative Atomic Mass	168,934598444 ± 0,000000326 Da
g-factor	0,9656 ± 0,0008
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	9,392 ± 0,018 d
spin	1/2
nuclear quadrupole moment	0
datum otkrića	1956
parity	-

decay mode	intensity
β⁻ (β⁻ decay)	100%

¹⁷⁰Er

Maseni broj	170
broj neutrona	102
Relative Atomic Mass	169,935471933 ± 0,000001488 Da
g-factor	0
natural abundance	14,91 ± 0,036
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada
spin	0
nuclear quadrupole moment	0
datum otkrića	1934
parity	+

decay mode	intensity
2β⁻ (double β⁻ decay)
α (α emission)

¹⁷¹Er

Maseni broj	171
broj neutrona	103
Relative Atomic Mass	170,938037372 ± 0,000001511 Da
g-factor	0,2628 ± 0,004
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	7,516 ± 0,002 h
spin	5/2
nuclear quadrupole moment	2,86 ± 0,09
datum otkrića	1938
parity	-

decay mode	intensity
β⁻ (β⁻ decay)	100%

¹⁷²Er

Maseni broj	172
broj neutrona	104
Relative Atomic Mass	171,939363461 ± 0,000004253 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	49,3 ± 0,5 h
spin	0
nuclear quadrupole moment	0
datum otkrića	1956
parity	+

decay mode	intensity
β⁻ (β⁻ decay)	100%

¹⁷³Er

Maseni broj	173
broj neutrona	105
Relative Atomic Mass	172,9424 ± 0,00021 Da
g-factor
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	1,434 ± 0,017 m
spin	7/2
nuclear quadrupole moment
datum otkrića	1972
parity	-

decay mode	intensity
β⁻ (β⁻ decay)	100%

¹⁷⁴Er

Maseni broj	174
broj neutrona	106
Relative Atomic Mass	173,94423 ± 0,00032 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	3,2 ± 0,2 m
spin	0
nuclear quadrupole moment	0
datum otkrića	1989
parity	+

decay mode	intensity
β⁻ (β⁻ decay)	100%

¹⁷⁵Er

Maseni broj	175
broj neutrona	107
Relative Atomic Mass	174,94777 ± 0,00043 Da
g-factor
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada	1,2 ± 0,3 m
spin	9/2
nuclear quadrupole moment
datum otkrića	1996
parity	+

decay mode	intensity
β⁻ (β⁻ decay)	100%

¹⁷⁶Er

Maseni broj	176
broj neutrona	108
Relative Atomic Mass	175,94994 ± 0,00043 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada
spin	0
nuclear quadrupole moment	0
datum otkrića	2012
parity	+

decay mode	intensity
β⁻ (β⁻ decay)

¹⁷⁷Er

Maseni broj	177
broj neutrona	109
Relative Atomic Mass	176,95399 ± 0,00054 Da
g-factor
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada
spin	1/2
nuclear quadrupole moment	0
datum otkrića	2012
parity	-

decay mode	intensity
β⁻ (β⁻ decay)

¹⁷⁸Er

Maseni broj	178
broj neutrona	110
Relative Atomic Mass	177,956779 ± 0,00064 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada
spin	0
nuclear quadrupole moment	0
datum otkrića	2012
parity	+

decay mode	intensity
β⁻ (β⁻ decay)

¹⁷⁹Er

Maseni broj	179
broj neutrona	111
Relative Atomic Mass	178,961267 ± 0,000537 Da
g-factor
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada
spin	3/2
nuclear quadrupole moment
datum otkrića	2018
parity	-

decay mode	intensity
β⁻ (β⁻ decay)
β⁻ n (β⁻-delayed neutron emission)

¹⁸⁰Er

Maseni broj	180
broj neutrona	112
Relative Atomic Mass	179,96438 ± 0,000537 Da
g-factor	0
natural abundance
Radioaktivnost	☢️ radioactive element
Vrijeme poluraspada
spin	0
nuclear quadrupole moment	0
datum otkrića	2018
parity	+

decay mode	intensity
β⁻ (β⁻ decay)
β⁻ n (β⁻-delayed neutron emission)

historija

otkrivač ili izumitelj	Carl Mosander
mjesto otkrića	Sweden
datum otkrića	1843
Etimologija	Named after the Swedish town, Ytterby.
pronunciation	UR-bi-em (engleski)

izvor

Abundance
Abundance in Earth's crust	3,5 mg/kg
natural abundance (okean)	0,00000087 mg/L
natural abundance (ljudsko tijelo)
natural abundance (Meteoroidi)	0,000018 %
natural abundance (Sunce)	0,0000001 %
Abundance in Universe	0,0000002 %

Nuclear Screening Constants

1	s	1.3263
2	p	4.346
2	s	17.7984
3	d	13.6397
3	p	20.3891
3	s	20.9231
4	d	35.7288
4	f	40.0216
4	p	32.8908
4	s	31.768
5	p	50.528
5	s	48.282
6	s	59.5238

Erbij[um] on ChemicalAid

Erbij[um] (Er)

Physical Property

Chemical Property

other

Isotopes of Erbium

142Er

143Er

144Er

145Er

146Er

147Er

148Er

149Er

150Er

151Er

152Er

153Er

154Er

155Er

156Er

157Er

158Er

159Er

160Er

161Er

162Er

163Er

164Er

165Er

166Er

167Er

168Er

169Er

170Er

171Er

172Er

173Er

174Er

175Er

176Er

177Er

178Er

179Er

180Er

historija

izvor

Nuclear Screening Constants

¹⁴²Er

¹⁴³Er

¹⁴⁴Er

¹⁴⁵Er

¹⁴⁶Er

¹⁴⁷Er

¹⁴⁸Er

¹⁴⁹Er

¹⁵⁰Er

¹⁵¹Er

¹⁵²Er

¹⁵³Er

¹⁵⁴Er

¹⁵⁵Er

¹⁵⁶Er

¹⁵⁷Er

¹⁵⁸Er

¹⁵⁹Er

¹⁶⁰Er

¹⁶¹Er

¹⁶²Er

¹⁶³Er

¹⁶⁴Er

¹⁶⁵Er

¹⁶⁶Er

¹⁶⁷Er

¹⁶⁸Er

¹⁶⁹Er

¹⁷⁰Er

¹⁷¹Er

¹⁷²Er

¹⁷³Er

¹⁷⁴Er

¹⁷⁵Er

¹⁷⁶Er

¹⁷⁷Er

¹⁷⁸Er

¹⁷⁹Er

¹⁸⁰Er