Transition metal

transition metalstransition elementtransition-metaltransition elementstransitionmetalfirst-row transition metaltransitional metalsd-d'' electronic transitionsearly and late transition elements
In chemistry, the term transition metal (or transition element) has three possible meanings:wikipedia
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F. Albert Cotton

F.A. Cotton Medal for Excellence in Chemical ResearchFrank Albert CottonF. A. Cotton
Cotton was recognized for his research on the chemistry of the transition metals.

Actinide

actinidesactinide seriesactinoid
While actinium and the late actinides (from americium onwards) behave similarly to the lanthanides, the elements thorium, protactinium, and uranium are much more similar to transition metals in their chemistry, with neptunium and plutonium occupying an intermediate position.

Yttrium

Y 90 YY-90
It is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a "rare-earth element".

Geoffrey Wilkinson

WilkinsonSir Geoffrey WilkinsonWilkinson, Sir Geoffrey
Sir Geoffrey Wilkinson FRS (14 July 1921 – 26 September 1996) was a Nobel laureate English chemist who pioneered inorganic chemistry and homogeneous transition metal catalysis.

Cadmium

CdCd 2+ cadmium compounds
Zinc, cadmium, and mercury are generally excluded from the transition metals, as they have the electronic configuration [ ]d 10 s 2, with no incomplete d shell.
Like zinc, it demonstrates oxidation state +2 in most of its compounds, and like mercury, it has a lower melting point than the transition metals in groups 3 through 11.

Post-transition metal

other metalPost-transition metalsB metals
The group 12 elements Zn, Cd and Hg may therefore, under certain criteria, be classed as post-transition metals in this case.
Post-transition metals are a set of metallic elements in the periodic table located between the transition metals to their left, and the metalloids to their right.

Metal

metalsmetal ionsmetal ion
As implied by the name, all transition metals are metals and thus conductors of electricity.
The strength of metallic bonds for different elemental metals reaches a maximum around the center of the transition metal series, as these elements have large numbers of delocalized electrons.

Zinc

ZnZn 2+ zinc alloy
Zinc, cadmium, and mercury are generally excluded from the transition metals, as they have the electronic configuration [ ]d 10 s 2, with no incomplete d shell.
The melting point is the lowest of all the d-block metals aside from mercury and cadmium; for this, among other reasons, zinc, cadmium, and mercury are often not considered to be transition metals like the rest of the d-block metals.

Periodic table

periodic table of elementsperiodic table of the elementsperiodic system
The d-block comprises groups 3 to 12 (or 3B to 2B in American group numbering) and contains all of the transition metals.

Iridium

IrIr-192Ir(III)
Although meitnerium, darmstadtium, and roentgenium are within the d-block and are expected to behave as transition metals analogous to their lighter congeners iridium, platinum, and gold, this has not yet been experimentally confirmed.
A very hard, brittle, silvery-white transition metal of the platinum group, iridium is the second-densest metal (after osmium) with a density of 22.56 g/cm3 as defined by experimental X-ray crystallography.

Gold

Aunative goldgold dust
Although meitnerium, darmstadtium, and roentgenium are within the d-block and are expected to behave as transition metals analogous to their lighter congeners iridium, platinum, and gold, this has not yet been experimentally confirmed.
Chemically, gold is a transition metal and a group 11 element.

Platinum

Ptcompounds of platinumdouble Platinum
Although meitnerium, darmstadtium, and roentgenium are within the d-block and are expected to behave as transition metals analogous to their lighter congeners iridium, platinum, and gold, this has not yet been experimentally confirmed.
It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal.

Titanium

Tititanium oretitanian
The maximum oxidation state in the first row transition metals is equal to the number of valence electrons from titanium (+4) up to manganese (+7), but decreases in the later elements.
It is a lustrous transition metal with a silver color, low density, and high strength.

Vanadium

Vvanadium steelV 3 Si
For example, compounds of vanadium are known in all oxidation states between −1, such as, and +5, such as. Vanadium(V) oxide (in the contact process), finely divided iron (in the Haber process), and nickel (in catalytic hydrogenation) are some of the examples.
It is a hard, silvery-grey, ductile, malleable transition metal.

Chromium

Crchromechromium(III)
It is a steely-grey, lustrous, hard and brittle transition metal.

Chemical element

elementelementschemical elements
The version of this classification used in the periodic tables presented here includes: actinides, alkali metals, alkaline earth metals, halogens, lanthanides, transition metals, post-transition metals, metalloids, reactive nonmetals, and noble gases.

Lanthanide

lanthanideslanthanoidlanthanide series
f → f transitions are symmetry forbidden (or Laporte-forbidden), which is also true of transition metals.

Iron

FeFe 2+ Fe(III)
Vanadium(V) oxide (in the contact process), finely divided iron (in the Haber process), and nickel (in catalytic hydrogenation) are some of the examples.
It is a metal that belongs to the first transition series and group 8 of the periodic table.

Manganese

Mnmanganese oreMn 2+
The maximum oxidation state in the first row transition metals is equal to the number of valence electrons from titanium (+4) up to manganese (+7), but decreases in the later elements. An example occurs in octahedral, high-spin complexes of manganese(II),
Manganese is a transition metal with a multifaceted array of industrial alloy uses, particularly in stainless steels.

Nickel

NiNi 2+ Nickel (Ni)
Vanadium(V) oxide (in the contact process), finely divided iron (in the Haber process), and nickel (in catalytic hydrogenation) are some of the examples.
Nickel belongs to the transition metals and is hard and ductile.

Meitnerium

MtUnnilennium109
Although meitnerium, darmstadtium, and roentgenium are within the d-block and are expected to behave as transition metals analogous to their lighter congeners iridium, platinum, and gold, this has not yet been experimentally confirmed.
It is a member of the 7th period and is placed in the group 9 elements, although no chemical experiments have yet been carried out to confirm that it behaves as the heavier homologue to iridium in group 9 as the seventh member of the 6d series of transition metals.

Oxidation state

oxidation numberoxidation statesoxidation
In the oxidation state +2 the ions have the electronic configuration [ ]…d 10.
Analogously for transition-metal compounds; CrO(O 2 ) 2 on the left has a total of 36 valence electrons (18 pairs to be distributed), and Cr(CO) 6 on the right has 66 valence electrons (33 pairs):

Niobium

NbcolumbiumNiobium (Nb)
Niobium is a light grey, crystalline, and ductile transition metal.

Period 4 element

fourth periodPeriod 44
It sees the first appearance of d-block (which includes transition metals) in the table.

Mercury(IV) fluoride

Mercury tetrafluorideonly one compound
The recent (though disputed and so far not reproduced independently) synthesis of mercury(IV) fluoride has been taken by some to reinforce the view that the group 12 elements should be considered transition metals, but some authors still consider this compound to be exceptional.
This means that the highest oxidation state mercury normally attains is II, and for this reason it is usually considered a post-transition metal instead of a transition metal.