Element: Lutetium

General data

Element name	Lutetium
Chemical symbol	Lu
Atomic number Z	71
Year discovered	1907
Standard state (25°C)	Solid
Category	Lanthanide
Block	f
Atomic mass	174.97
CPK color	#00AB24

Physical properties

Melting point	1936 K (1663 °C)
Boiling point	3675 K (3402 °C)
Density	9.84 g/cm³

Energy properties

First ionization energy	5.426 eV
Electron affinity	no data

Atomic structure

Protons	71 (Atomic number)
Neutrons (Lu-175, most abundant isotope)	104
Electrons	71
Electron configuration	[Xe] 6s² 4f¹⁴ 5d¹
Oxidation states	+3
Electronegativity (Pauling)	1.27
Atomic radius (van der Waals)	221 pm

Ionization energies - NIST ASD (71 states)

State	Charge	Ioniz. energy (eV)	Type
Lu I	0+	5.425871 ± 0.000012	measured
Lu II	1+	14.13 ± 0.05	semi-empirical
Lu III	2+	20.9594 ± 0.0012	measured
Lu IV	3+	45.249 ± 0.025	semi-empirical
Lu V	4+	66.8 ± 0.3	semi-empirical
Lu VI	5+	98 ± 5	calculated
Lu VII	6+	117 ± 6	calculated
Lu VIII	7+	136 ± 7	calculated
Lu IX	8+	159 ± 8	calculated
Lu X	9+	185 ± 9	calculated
Lu XI	10+	205 ± 10	calculated
Lu XII	11+	238 ± 12	calculated
Lu XIII	12+	276 ± 14	calculated
Lu XIV	13+	305 ± 15	calculated
Lu XV	14+	328 ± 16	calculated
Lu XVI	15+	361 ± 19	calculated
Lu XVII	16+	399 ± 20	calculated
Lu XVIII	17+	438 ± 22	calculated
Lu XIX	18+	476 ± 24	calculated
Lu XX	19+	520 ± 30	calculated
Lu XXI	20+	560 ± 30	calculated
Lu XXII	21+	600 ± 30	calculated
Lu XXIII	22+	630 ± 30	calculated
Lu XXIV	23+	670 ± 30	calculated
Lu XXV	24+	713 ± 7	calculated
Lu XXVI	25+	941 ± 4	calculated
Lu XXVII	26+	985 ± 4	calculated
Lu XXVIII	27+	1032 ± 4	calculated
Lu XXIX	28+	1081 ± 4	calculated
Lu XXX	29+	1130 ± 4	calculated
Lu XXXI	30+	1178 ± 4	calculated
Lu XXXII	31+	1242 ± 4	calculated
Lu XXXIII	32+	1292 ± 4	calculated
Lu XXXIV	33+	1345 ± 5	calculated
Lu XXXV	34+	1395 ± 5	calculated
Lu XXXVI	35+	1591 ± 5	calculated
Lu XXXVII	36+	1641 ± 5	calculated
Lu XXXVIII	37+	1696 ± 4	calculated
Lu XXXIX	38+	1747 ± 4	calculated
Lu XL	39+	1875 ± 4	calculated
Lu XLI	40+	1933 ± 4	calculated
Lu XLII	41+	2067 ± 4	calculated
Lu XLIII	42+	2125.5 ± 1.1	semi-empirical
Lu XLIV	43+	3590 ± 4	calculated
Lu XLV	44+	3706 ± 4	calculated
Lu XLVI	45+	3828 ± 4	calculated
Lu XLVII	46+	3960 ± 4	calculated
Lu XLVIII	47+	4086 ± 4	calculated
Lu XLIX	48+	4211 ± 4	calculated
Lu L	49+	4403 ± 4	calculated
Lu LI	50+	4532 ± 4	calculated
Lu LII	51+	4673 ± 4	calculated
Lu LIII	52+	4803 ± 4	calculated
Lu LIV	53+	5168 ± 5	calculated
Lu LV	54+	5282 ± 5	calculated
Lu LVI	55+	5408 ± 5	calculated
Lu LVII	56+	5525 ± 5	calculated
Lu LVIII	57+	5937 ± 6	calculated
Lu LIX	58+	6070 ± 6	calculated
Lu LX	59+	6326 ± 7	calculated
Lu LXI	60+	6452 ± 10	calculated
Lu LXII	61+	14228 ± 12	calculated
Lu LXIII	62+	14542 ± 15	calculated
Lu LXIV	63+	14890 ± 19	calculated
Lu LXV	64+	15211 ± 24	calculated
Lu LXVI	65+	16730 ± 30	calculated
Lu LXVII	66+	17120 ± 40	calculated
Lu LXVIII	67+	17610 ± 40	calculated
Lu LXIX	68+	17928.05 ± 0.16	calculated
Lu LXX	69+	72322.87 ± 0.15	calculated
Lu LXXI	70+	73804.35 ± 0.24	calculated

Value type as given by NIST ASD: measured - from evaluated experimental data; calculated - from ab initio calculations (mostly highly ionised atoms that have not been measured; for the simplest ones, e.g. H I, the calculation is more accurate than measurement); semi-empirical - from interpolation, extrapolation or another semi-empirical method.

Photos

Photo of the element: Lutetium (Lu) — © images-of-elements.com (CC BY 3.0)

Isotopes (39)

A	N	Half-life	Decay
Lu-150	79	45 ms	p
Lu-151	80	79 ms	EC/β⁺
Lu-152	81	650 ms	EC/β⁺
Lu-153	82	0.9 s	α
Lu-154	83	unknown	EC/β⁺
Lu-155	84	67 ms	α
Lu-156	85	494 ms	α
Lu-157	86	7.6 s	α
Lu-158	87	10.6 s	EC/β⁺
Lu-159	88	12.1 s	EC/β⁺
Lu-160	89	36.1 s	EC/β⁺
Lu-161	90	77 s	EC/β⁺
Lu-162	91	1.37 min	EC/β⁺
Lu-163	92	4.01 min	EC/β⁺
Lu-164	93	3.15 min	EC/β⁺
Lu-165	94	10.74 min	EC/β⁺
Lu-166	95	2.65 min	EC/β⁺
Lu-167	96	52.0 min	EC/β⁺
Lu-168	97	5.5 min	EC/β⁺
Lu-169	98	34.06 h	EC/β⁺
Lu-170	99	2.01 d	EC/β⁺
Lu-171	100	8.25 d	EC/β⁺
Lu-172	101	6.702 d	EC/β⁺
Lu-173	102	1.37 a	EC
Lu-174	103	3.31 a	EC/β⁺
Lu-175	104	stable	-
Lu-176	105	3.714×10¹⁰ a	β⁻
Lu-177	106	6.6472 d	β⁻
Lu-178	107	28.4 min	β⁻
Lu-179	108	4.59 h	β⁻
Lu-180	109	5.6 min	β⁻
Lu-181	110	3.5 min	β⁻
Lu-182	111	2.0 min	β⁻
Lu-183	112	58 s	β⁻
Lu-184	113	19 s	β⁻
Lu-185	114	unknown	β⁻
Lu-186	115	unknown	β⁻
Lu-187	116	unknown	β⁻
Lu-188	117	unknown	β⁻

Data sources

PubChem Periodic Table API - Retrieved on 29 June 2026 - licence: CC0
IUPAC CIAAW - Abridged Standard Atomic Weights 2024 - Table version: 2024 - licence: Public domain
NNDC Wallet Cards 2023 - Data as of 15 October 2024 - licence: Public domain
Images of Elements - Retrieved on 29 June 2026 - licence: CC BY 3.0

More about the data sources