28th April 1921. Charles Rugeley Bury?
The awkward squad of the chemical elements in the Periodic Table are the Transition Metals. Fitting into the centre of the Table they possess the properties of metals, are very hard, have high melting and boiling points and loosely bound electrons, so are highly conductive and malleable as with Copper and Silver.
They include the common metals such as iron, silver (a noble transition element having the highest thermal and electrical conductivity of any metal), gold and copper, and some not so common as Zirconium and Yttrium. They are less reactive than the alkali and alkaline earths, they form colour compounds and are good conductors of electricity.
These metals have valence (bonding) electrons present in more than one outer shell, so they have several oxidation states: iron, nickel and cobalt also produce a magnetic field.
The pioneer of electron configuration in atoms, for most of the Periodic Table, and the person who introduced the term ‘Transition Metals’, was the Henley on Thames born Charles Rugeley Bury, whose paper appeared Today in 1921 in The Journal of The American Chemical Society.(1)
Uses of transition metals are many: cast iron for manholes, copper in many uses, zinc in galvanisation as an anti-corrosive, and is also a component of copper, iron and chrome and cobalt in bright colours in stained glass.
They are also vital as catalysts, with iron used in the Haber Process to make Ammonia when combined with Hydrogen and Nitrogen. Then Nickel is used in the Hydrogenation (of Carbon-Carbon Bond), the reaction at the heart of making Margarine from Vegetable Oil.
(1) Vol. 43 p 1602-1609. Bury ( (29.7.1890-30.12.1968).
In 1935 Bury’s seminal paper related the appearance of colour in nearly all well-known families of organic dyestuffs to the presence of resonance (as electronic de-localisation was described), between two often strictly equivalent molecular electronic structures as for example in Dobner’s Violet. Bury also offered equivalent formulations for fifteen dyestuff families and instanced indigo as a non-complier.
Transition Metals have incomplete inner valence shells and can use their inner shells/orbits as valence to bond to other elements. For example iron (Fe) as well as other states can be +2 and+3 and chromium (Cr) can have +2 +3 +6. The + oxidation states allow Transition Elements to form many different ionic/part ionic compounds.
Ref: GCSE Bitesize on transition elements.
Ref: ChemTeam site.
Ref: Periodic Table its story and its significance Eric R Scerri 2007.
Ref: encyclopedia.com/Bury, Charles Rugeley.