Transition Metals

Beryl Powder: Transition metal as “an element whose atom has a partially filled d sub-shell, or which can give rise to cations with an incomplete d sub-shell”.The transition metals are placed in the centre of the periodic table, between groups 2 and 3. They are generally hard and dense, and less reactive than the alkali metals. Iron, copper, silver and gold are important transition metals.

Beryl Powder: Transition metals form coloured compounds, are good conductors of heat and electricity, can be hammered or bent into shape easily, less reactive than alkali metals such as sodium, have high melting points, are hard and tough, have high densities, form paramagnetic compounds due to the presence of unpaired d electrons.Transition metals can bound to variety of ligands, allowing for a wide variety of transition metal complexes.

Beryl Powder: Transition metal complexes are important in catalysis, photochemistry, materials synthesis, and biological systems. Transition metals provide a surface on which a reaction can take place. Reactants are adsorbed onto the surface of the metal and held in place while a reaction occurs. Transition metal ions make good catalysts because of their ability to change oxidation state by gaining or losing electrons.

Beryl Powder: Transition metal compounds are paramagnetic when they have one or more unpaired d electrons. In octahedral complexes with between four and seven d electrons both high spin and low spin states are possible. Tetrahedral transition metal complexes such as [fecl4]^2- are high spin because the crystal field splitting  is small sso that the energy to be gained by the virtue of the electrons being in lower energy orbitals is always less than the energy needed to pair up the spins.

Beryl Powder: In general, transition metals possess a high density and high melting points and boiling points. These properties are due to metallic bonding by delocalized d electrons, leading to cohesion which increases with the number of shared electrons. However the group 12 metals have much lower melting and boiling points since their full d subshells prevent d–d bonding, which again tends to differentiate them from the accepted transition metals.