Groups 3–12 — the d-block, and most of the metals you have ever touched

Transition metals

Iron, copper, gold, silver, titanium, chromium, nickel, zinc. The thirty-eight elements of the d-block are hard, dense, high-melting, conductive, and — uniquely — capable of forming ions in several different charges. That flexibility is why they catalyse, why they colour, and why they are magnetic.

Members
38
Group
3–12
Configuration
(n−1)d¹⁻¹⁰ ns¹⁻²
Radioactive
10

Highlighted in the periodic table

Every member

The 38 transition metals

21 Sc Scandium 44.956 u A rare-earth-adjacent metal that makes aluminium alloys far stronger, at a price that keeps it exotic. solid 22 Ti Titanium 47.867 u As strong as steel, 45% lighter, and immune to seawater — the metal of implants, jets and deep submersibles. solid 23 V Vanadium 50.942 u A transition metal that turns four different colours in solution depending on its oxidation state. solid 24 Cr Chromium 51.996 u The element that puts the shine in chrome and the "stainless" in stainless steel. solid 25 Mn Manganese 54.938 u Essential in trace amounts, brittle in bulk, and the reason your steel does not shatter in the cold. solid 26 Fe Iron 55.845 u The most common element on Earth by mass, the endpoint of stellar fusion, and the metal that named an age. solid 27 Co Cobalt 58.933 u The blue in medieval stained glass and Ming porcelain, and half of the magnets that hold hard drives together. solid 28 Ni Nickel 58.693 u Tough, corrosion-resistant and magnetic — and the second-biggest ingredient in stainless steel. solid 29 Cu Copper 63.546 u The first metal humans smelted, and still the nervous system of the electrified world. solid 30 Zn Zinc 65.38 u The sacrificial metal: zinc corrodes so that the steel it coats does not. solid 39 Y Yttrium 88.906 u A "rare earth" that is not actually rare, and the reason your phone screen glows the right colours. solid 40 Zr Zirconium 91.224 u Effectively transparent to neutrons, which is why it lines the fuel rods in nearly every nuclear reactor. solid 41 Nb Niobium 92.906 u A superconducting metal that carries the current in every MRI magnet on Earth. solid 42 Mo Molybdenum 95.95 u The refractory workhorse: molybdenum keeps its strength at temperatures that soften almost everything else. solid 43 Tc Technetium 98 u The first element made by humans rather than found — and the lightest with no stable isotope at all. radioactive synthetic solid 44 Ru Ruthenium 101.07 u A platinum-group metal that hardens its neighbours and catalyses ammonia synthesis. solid 45 Rh Rhodium 102.906 u The most expensive precious metal on Earth by weight, and the reason your car's exhaust is not toxic. solid 46 Pd Palladium 106.42 u The metal that soaks up hydrogen like a sponge — up to 900 times its own volume. solid 47 Ag Silver 107.868 u The best electrical and thermal conductor of any element, and an antimicrobial known since antiquity. solid 48 Cd Cadmium 112.414 u A soft, toxic metal that gave the world rechargeable NiCd cells and the brilliant yellow of old paint. solid 72 Hf Hafnium 178.49 u Chemically almost identical to zirconium, yet its exact opposite in a reactor — it eats neutrons. solid 73 Ta Tantalum 180.948 u A metal that shrugs off almost every acid and is biocompatible enough for surgical implants. solid 74 W Tungsten 183.84 u The highest melting point of any metal — 3,422 degrees C — and the filament of the incandescent age. solid 75 Re Rhenium 186.207 u One of the rarest elements in the crust, and the metal that lets jet turbines run hotter. solid 76 Os Osmium 190.23 u The densest naturally occurring element: a litre of osmium weighs 22.6 kg. solid 77 Ir Iridium 192.217 u The most corrosion-resistant metal known, and the fingerprint of the asteroid that ended the dinosaurs. solid 78 Pt Platinum 195.084 u The catalyst metal: platinum makes reactions happen that would otherwise need impossible conditions. solid 79 Au Gold 196.967 u Chemically almost inert, endlessly ductile, and valued by every civilisation that ever found it. solid 80 Hg Mercury 200.592 u The only metal that is liquid at room temperature — and a potent neurotoxin. liquid 104 Rf Rutherfordium 267 u The first transactinide — and chemically a heavier cousin of hafnium, not an actinide at all. radioactive synthetic solid 105 Db Dubnium 268 u Named after Dubna, the Russian town where much of superheavy chemistry was pioneered. radioactive synthetic solid 106 Sg Seaborgium 271 u Named for Glenn Seaborg while he was still alive — a first for the periodic table. radioactive synthetic solid 107 Bh Bohrium 272 u A superheavy element whose chemistry, tested one atom at a time, behaves as predicted for group 7. radioactive synthetic solid 108 Hs Hassium 270 u The heaviest element whose chemical properties have been experimentally confirmed. radioactive synthetic solid 109 Mt Meitnerium 276 u Named for Lise Meitner, who explained nuclear fission but was left off the Nobel Prize. radioactive synthetic solid 110 Ds Darmstadtium 281 u Created at Darmstadt in 1994 by fusing nickel and lead nuclei. radioactive synthetic solid 111 Rg Roentgenium 280 u Named for the discoverer of X-rays, and predicted to be chemically like gold. radioactive synthetic solid 112 Cn Copernicium 285 u Predicted to be a volatile liquid — a metal that behaves almost like a noble gas. radioactive synthetic liquid

What defines them

Three things that make a transition metal

01

A partly filled d subshell

The defining feature. Because d orbitals sit close in energy to the outer s orbital, transition metals can lose a variable number of electrons — iron gives up two or three, manganese anything from two to seven. Each charge state is a different chemistry.

02

Colour comes from d-orbital splitting

Surround a transition-metal ion with ligands and its five d orbitals split into groups of slightly different energy. Visible light promotes electrons across that gap, and the colour you see is whatever is left over. This is why copper sulfate is blue, why rubies are red and why the same element can give several different colours.

03

Catalysis and magnetism

Partly filled d shells make excellent temporary bonding partners — the basis of industrial catalysis, from ammonia synthesis over iron to catalytic converters over platinum. The same unpaired d electrons give iron, cobalt and nickel their ferromagnetism.

Periodic trends

How they change across the family

Across a row, atomic radius changes remarkably little — added protons pull inward while added d electrons shield outward, roughly cancelling. Densities and melting points peak in the middle of each row, where the maximum number of electrons is available for metallic bonding: tungsten melts at 3,695 K, the highest of any metal.

In the world

What they are used for

Iron

Steel — the single most-used metal by a wide margin, and the structural basis of the industrial world.

Copper

Electrical wiring, plumbing, and the printed circuits in every device you own. Second only to silver as a conductor, and vastly cheaper.

Titanium

Aerospace, marine hardware and medical implants: as strong as steel, 45% lighter, and effectively immune to seawater and body fluids.

Chromium & nickel

Together they make stainless steel. Chromium forms an invisible, self-healing oxide layer; nickel adds toughness and corrosion resistance.

Platinum group

Catalysis. Platinum, palladium and rhodium clean vehicle exhaust; rhodium is periodically the most expensive metal on Earth.

Gold & silver

Currency, jewellery, and — because gold never corrodes — the contact plating in high-reliability electronics.

Handling

Safety

Enormously varied. Iron, zinc, copper, cobalt, manganese, molybdenum and chromium(III) are essential trace nutrients; chromium(VI) is a potent carcinogen. Cadmium and mercury are cumulative poisons. Nickel is the most common contact allergen in the world. Fine metal powders of many transition metals are pyrophoric.

Worth knowing

  • Technetium (43) was the first element made rather than found, and remains the lightest with no stable isotope.
  • Mercury is the only metal that is liquid at room temperature — a consequence of relativistic effects on its 6s electrons.
  • All the gold ever mined would fit in a cube about 22 metres on a side.

Common questions

About the transition metals

What makes an element a transition metal?

The strict IUPAC definition is an element whose atoms have a partly filled d subshell, or which can form a cation with one. That technically excludes zinc, cadmium and mercury, whose d shells are always full — but they sit in the d-block and are almost always taught with the group. This site follows the common convention and includes them.

Why do transition metals form coloured compounds?

Because their d orbitals are split into slightly different energies by the surrounding ligands, and the gap happens to match visible-light photon energies. An electron absorbs a photon to jump the gap; you see the complementary colour. Zinc compounds are colourless precisely because zinc's d shell is full, leaving no gap to jump.

Why are they so much denser than group 1 and 2 metals?

More electrons per atom are available for metallic bonding — up to a dozen — so the atoms pull together far more tightly. That same strong bonding gives them their high melting points and hardness. Osmium, in the middle of row 6, is the densest element there is at 22.6 g/cm³.

Keep going

The other nine families

6 Alkali metals Li Na K Rb Cs Fr 6 Alkaline earth metals Be Mg Ca Sr Ba Ra 12 Post-transition metals Al Ga In Sn Tl Pb Bi 7 Metalloids B Si Ge As Sb Te At 7 Nonmetals H C N O P S Se 5 Halogens F Cl Br I Ts 7 Noble gases He Ne Ar Kr Xe Rn Og 15 Lanthanides La Ce Pr Nd Pm Sm Eu 15 Actinides Ac Th Pa U Np Pu Am