Element: Palladium

General data

Element name	Palladium
Chemical symbol	Pd
Atomic number Z	46
Year discovered	1803
Standard state (25°C)	Solid
Category	Transition metal
Block	d
Atomic mass	106.42
CPK color	#6985

Physical properties

Melting point	1828.05 K (1554.90 °C)
Boiling point	3236 K (2963 °C)
Density	12 g/cm³

Energy properties

First ionization energy	8.337 eV
Electron affinity	0.557 eV

Atomic structure

Protons	46 (Atomic number)
Neutrons (Pd-106, most abundant isotope)	60
Electrons	46
Electron configuration	[Kr] 4d¹⁰
Oxidation states	+3, +2
Electronegativity (Pauling)	2.2
Atomic radius (van der Waals)	202 pm

Ionization energies - NIST ASD (46 states)

State	Charge	Ioniz. energy (eV)	Type
Pd I	0+	8.336839 ± 0.00001	measured
Pd II	1+	19.43 ± 0.12	semi-empirical
Pd III	2+	32.93	semi-empirical
Pd IV	3+	46 ± 1.7	calculated
Pd V	4+	61 ± 1.9	calculated
Pd VI	5+	84.1 ± 2	calculated
Pd VII	6+	101 ± 2	calculated
Pd VIII	7+	120 ± 2.1	calculated
Pd IX	8+	141 ± 2.2	calculated
Pd X	9+	159.9 ± 2.2	calculated
Pd XI	10+	238.57 ± 0.12	semi-empirical
Pd XII	11+	260 ± 2.5	calculated
Pd XIII	12+	286 ± 3	calculated
Pd XIV	13+	311 ± 3	calculated
Pd XV	14+	342 ± 3	calculated
Pd XVI	15+	369.1 ± 0.15	semi-empirical
Pd XVII	16+	427 ± 3	calculated
Pd XVIII	17+	457.5 ± 0.15	semi-empirical
Pd XIX	18+	810 ± 3	calculated
Pd XX	19+	869 ± 4	calculated
Pd XXI	20+	933 ± 4	calculated
Pd XXII	21+	1000 ± 4	calculated
Pd XXIII	22+	1065 ± 4	calculated
Pd XXIV	23+	1145 ± 4	calculated
Pd XXV	24+	1218 ± 4	calculated
Pd XXVI	25+	1290 ± 4	calculated
Pd XXVII	26+	1366 ± 4	calculated
Pd XXVIII	27+	1438 ± 4	calculated
Pd XXIX	28+	1644 ± 5	semi-empirical
Pd XXX	29+	1706.2 ± 1.8	semi-empirical
Pd XXXI	30+	1781.3 ± 2.3	semi-empirical
Pd XXXII	31+	1869 ± 7	semi-empirical
Pd XXXIII	32+	1962 ± 4	semi-empirical
Pd XXXIV	33+	2016 ± 9	semi-empirical
Pd XXXV	34+	2181 ± 3	semi-empirical
Pd XXXVI	35+	2248.87 ± 0.07	semi-empirical
Pd XXXVII	36+	5284 ± 3	semi-empirical
Pd XXXVIII	37+	5475 ± 9	semi-empirical
Pd XXXIX	38+	5683 ± 11	semi-empirical
Pd XL	39+	5880 ± 40	semi-empirical
Pd XLI	40+	6242 ± 7	semi-empirical
Pd XLII	41+	6469 ± 5	semi-empirical
Pd XLIII	42+	6759 ± 6	semi-empirical
Pd XLIV	43+	6943.097 ± 0.022	calculated
Pd XLV	44+	28776.032 ± 0.014	calculated
Pd XLVI	45+	29622.678 ± 0.007	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: Palladium (Pd) — © images-of-elements.com (CC BY 3.0)

Isotopes (42)

A	N	Half-life	Decay
Pd-90	44	unknown	EC/β⁺
Pd-91	45	32 ms	EC/β⁺
Pd-92	46	1.06 s	EC/β⁺
Pd-93	47	1.17 s	EC/β⁺
Pd-94	48	9.4 s	EC/β⁺
Pd-95	49	7.4 s	EC/β⁺
Pd-96	50	122 s	EC/β⁺
Pd-97	51	3.1 min	EC/β⁺
Pd-98	52	17.7 min	EC/β⁺
Pd-99	53	21.4 min	EC/β⁺
Pd-100	54	3.63 d	EC
Pd-101	55	8.47 h	EC/β⁺
Pd-102	56	stable	-
Pd-103	57	17.00 d	EC
Pd-104	58	stable	-
Pd-105	59	stable	-
Pd-106	60	stable	-
Pd-107	61	6.5×10⁶ a	β⁻
Pd-108	62	stable	-
Pd-109	63	13.437 h	β⁻
Pd-110	64	stable	-
Pd-111	65	23.6 min	β⁻
Pd-112	66	21.027 h	β⁻
Pd-113	67	89 s	β⁻
Pd-114	68	2.42 min	β⁻
Pd-115	69	25 s	β⁻
Pd-116	70	11.7 s	β⁻
Pd-117	71	4.3 s	β⁻
Pd-118	72	1.9 s	β⁻
Pd-119	73	0.88 s	β⁻
Pd-120	74	490 ms	β⁻
Pd-121	75	290 ms	β⁻
Pd-122	76	195 ms	β⁻
Pd-123	77	109 ms	β⁻
Pd-124	78	94 ms	β⁻
Pd-125	79	64.2 ms	β⁻
Pd-126	80	48.6 ms	β⁻
Pd-127	81	38 ms	β⁻
Pd-128	82	36 ms	β⁻
Pd-129	83	31 ms	β⁻
Pd-130	84	unknown	β⁻
Pd-131	85	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