Questions and Answers
What defines the coordination number of a central atom in a complex ion?
In the complex ion K4[Fe(CN)6], what is the coordination sphere?
Which of the following complex ions exhibits a square planar geometry?
What type of ligands are C2O4 and en in [Fe(C2O4)3] and [Co(en)3], respectively?
Signup and view all the answers
Which coordination polyhedron is associated with the complex [Co(NH3)6]?
Signup and view all the answers
Which of the following statements about linkage isomerism is correct?
Signup and view all the answers
In which of the following compounds does ionization isomerism occur?
Signup and view all the answers
What distinguishes cis-[CrCl2(ox)2] from trans-[CrCl2(ox)2]?
Signup and view all the answers
Which of the following complex ions exhibits coordination isomerism?
Signup and view all the answers
Which statement correctly describes solvate isomerism?
Signup and view all the answers
Study Notes
Coordination Numbers
- Coordination number for Pt in [PtCl6] is 6; for Ni in [Ni(NH3)4] is 4.
- Both Fe in [Fe(C2O4)3] and Co in [Co(en)3] have a coordination number of 6, due to bidentate ligands like C2O4 and en (ethane-1,2-diamine).
Sigma and Pi Bonds
- Coordination number is determined by the number of sigma bonds with ligands; pi bonds are not considered.
Coordination Sphere
- Coordination sphere consists of the central atom/ion and its ligands in square brackets, e.g., in K4[Fe(CN)6], the sphere is [Fe(CN)6], and K is the counter ion.
Coordination Polyhedron
- The arrangement of ligands around the central atom defines a coordination polyhedron; common shapes include octahedral (e.g., [Co(NH3)6]), tetrahedral (e.g., [Ni(CO)4]), and square planar (e.g., [PtCl4]).
Isomerism Types
- Linkage Isomerism: Exists with ambidentate ligands; e.g., NCS– can bind through nitrogen (M–NCS) or sulfur (M–SCN).
- Coordination Isomerism: Involves interchange of ligands between cationic and anionic entities, e.g., [Co(NH3)6][Cr(CN)6] vs. [Cr(NH3)6][Co(CN)6].
- Ionisation Isomerism: Occurs when counter ions can also act as ligands; e.g., [Co(NH3)5(SO4)]Br vs. [Co(NH3)5Br]SO4.
- Solvate Isomerism: Known as hydrate isomerism when water is a solvent; changes in ligand ratios demonstrate different complexes and color changes.
Coordination Compound Colors
- Color in transition metal complexes arises from electronic transitions in d orbitals; e.g., rubies exhibit color due to Cr ions in Al2O3, and emeralds have Cr in beryl.
Importance and Applications of Coordination Compounds
- Critical in analytical chemistry for qualitative/quantitative analysis using color reactions from metal-ligand complexes.
- Used in the extraction of metals; e.g., gold forms [Au(CN)2] with cyanide, allowing for purification.
- Significant in biological systems, as well as in industry and medicine; contributes to understanding bonding, reactions, and molecular structure.
Theoretical Perspectives
- Werner's theory highlighted primary (ionic) and secondary (covalent) linkages in coordination compounds, predicting geometrical shapes based on isomerism.
- Valence Bond Theory (VBT) explains the formation and shapes but lacks quantitative magnetic behavior predictions.
- Crystal Field Theory (CFT) discusses d orbital energy splitting in relation to ligand fields, allowing for estimations of energies and stabilities.
- Synergic bonding in metal carbonyls includes both σ and π character, providing stability to these compounds.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on coordination numbers and complex ions! This quiz covers examples such as [PtCl6]2+ and [Ni(NH3)4] as well as [Fe(C2O4)3] and [Co(en)3]. Understand the significance of coordination numbers in various transition metal complexes.
