Chapter 23 - Transition Metals Chemistry and Coordination Compounds

23.1 - Properties of the Transition Metals

• Strong metallic bonding result from the combination of tight packing and small atomic size.
  • As a result, transition metals have greater densities, melting points, boiling points, and fusion and vaporization temps.
• Transition metal complexes have a wide range of oxidation states
  • It's worth noting that each element's usual oxidation states are +2, +3, or both.
  • The +3 oxidation states are more stable towards the start of the series, whereas the +2 oxidation levels are more stable toward the end.
• The nuclear numbers increase, the outer shell is filled with electrons and by adding protons the nuclear charge increases.
• The external electrons weakly protect each other from the extra nuclear charge in the third period – sodium to argon.
  • Therefore, atomic radiation rapidly decreases from sodium to argon, with increasing energy from electronegativities and ionizations.

23.2 - Chemistry of Iron and Copper

• Iron is the second most prevalent metal in the Earth's crust, behind aluminum.
  • It can be found in a variety of ores, including hematite (Fe2O3), siderite (FeCO3), and magnetite (Fe3O4).
• Copper, a rare element that makes up 6.8% of the Earth's crust by mass, can be found in its natural state as well as in ores like chalcopyrite, CuFeS2.
• Unclean copper can be electrolysically purified.
• Copper has the highest electrical conductivity after silver, too expensive for large-scale use. It's also a good heat pipeline.
  • In alloys, electrical cables, tubes, and coins copper is used.

23.3 - Coordination Compounds

• A coordination compound is made up of a complexion and a counter ion in most cases.
• Ligands are the molecules or ions that surround the metal in a complexion.
• The donor atom is the atom in a ligand that is directly bonded to the metal atom.
  • The number of donor atoms surrounding the core metal atom in a complexion is known as the coordination number in coordination compounds.
• Ligands are characterized as monodentate, bidentate, or polydentate depending on the number of donor atoms present.
  • H2O and NH3 are monodentate ligands, meaning they each have only one donor atom.
• Because of their claw-like capacity to hold the metal atom, bidentate and polydentate ligands are also known as chelating agents.

23.4 - Structure of Coordination Compounds

• Stereoisomers that cannot be interconverted without breaking a chemical link are known as geometric isomers.
  • Geometric isomers are commonly seen in pairs.
  • To identify one geometric isomer of a chemical from the other, we use the terms "cis" and "trans."
  • Cis denotes that two atoms are next to each other in the structural formula, while trans denotes that the atoms are on opposing sides.
  • Colors, melting temperatures, dipole values, and chemical reactivities of cis and trans isomers of coordination compounds are often considerably different.
• Optical isomers are mirror images that cannot be superimposed.
• Plane-polarized light vibrates only in one plane, unlike conventional light, which vibrates in all directions.
  • The rotation of polarized light by optical isomers is measured using a polarimeter.

23.5 - Bonding in Coordination Compounds: Crystal Field Theory

• When ligands are present, the crystal field splitting is the energy difference between two sets of d orbitals in a metal atom.
• Chemists calculated the crystal splitting for each ligand using spectroscopic data for several complexes with the same metal ion but different ligands, and established a spectrochemical series, which is a list of ligands arranged in increasing order of their ability to split the d orbital energy levels.

23.6 - Reactions of Coordination Compounds

• A complexion that conducts very sluggish exchange reactions is called an inert complex.
• It demonstrates that a chemically reactive species is not always thermodynamically unstable.
  • The energy of activation, which is considerable in this situation, determines the rate of reaction.
• The labile complex is known to complexes such as tetracyanonickelate(II) because they are subjected to rapid reactions of the ligand.
  • A thermodynamically stable species is therefore not unreactive.

23.7 - Applications of Coordination Compounds

• Coordination compounds are found in biological systems and are used in a variety of settings, including the household, industry, and medicine.
• The tripolyphosphate ion is an effective, stability and solubility of chelating agent with Ca2+ ions. The detergent industry has revolutionized sodium tripolyphosphate.
  • But because the phosphates are plant nutrients, phosphate-based waste water released in rivers and lakes leads to the development of algae, which leads to oxygen depletion.
• Most or all water life eventually succumbs under these conditions. This is known as eutrophication.
  • As a result, since the 1970s, many States have prohibited phosphate detergents and producers have rewritten their products for the purpose of phosphates removal.