TRB PG Assistant - Cages and clusters: metal cluster chemistry including metal carbonyls and halide type clusters One Line Questions & Answers

1. What is the typical coordination number of a metal atom in the core of a metal halide cluster like [Nb6Cl12]2+? — 12

2. What does the 'nido' designation in Wade's Rules indicate about a cluster's structure? — A polyhedral cage with one vertex missing

3. The structure of the [Nb6Cl12]2+ cluster can be described as: — An octahedral arrangement of metal atoms surrounded by edge-bridging chlorides

4. The cluster formula [Os10(CO)32]^2- has a skeletal electron count that suggests a structure related to: — A closed polyhedral cage

5. What is the defining characteristic of a metal cluster compound? — Multiple metal atoms bonded directly to each other

6. The synthesis of heteronuclear metal clusters involves: — At least two different types of metal atoms

7. In the context of metal clusters, 'ligand stripping' refers to: — Removing ligands from the cluster

8. In metal carbonyl clusters, the metal-metal bond order is generally considered to be: — Variable and can be fractional

9. The synthesis of metal clusters often involves reactions under: — High pressure of CO and elevated temperature

10. In the context of metal clusters, 'interstitial atoms' refer to: — Atoms located within the voids of the metal framework

11. The term 'carbonyl' in metal carbonyl clusters refers to the presence of: — Carbon monoxide (CO) ligands

12. Which of the following is a common bridging ligand in metal carbonyl clusters? — CO (bridging)

13. The bridging mode of a CO ligand in a metal cluster is often denoted by: — COb

14. The compound Re3Cl11^2- is an example of a metal halide cluster with: — Discrete trinuclear units

15. What is the primary driving force for the formation of metal-metal bonds in clusters? — Formation of delocalized bonding orbitals

16. Which of the following is a common bridging halide in metal halide clusters? — Cl-

17. Which of the following is a common example of a metal carbonyl cluster? — Co2(CO)8

18. Which of the following metal carbonyls is a simple mononuclear complex and NOT a cluster? — Ni(CO)4

19. Which metal cluster is famously known for its 'snowman' structure? — Rh6(CO)16

20. The 'delta bond' is a type of metal-metal bond that can be found in clusters, particularly those involving: — Second and third-row transition metals

21. Which element is known for forming a wide variety of stable metal carbonyl clusters? — Iron

22. The famous 'infinite chains' of metal halide clusters often exhibit: — High electrical conductivity

23. Metal carbonyl clusters are often formed from transition metals in which oxidation state? — Low or zero oxidation states

24. Which of the following is NOT a typical characteristic of metal carbonyl clusters? — Tendency to form extended ionic lattices

25. The synthesis of metal halide clusters often involves: — Reductive condensation of metal halides

26. What is the typical charge of the metal atoms in common metal carbonyl clusters? — Neutral or slightly negative

27. Which rule is often used to predict the structure of metal carbonyl clusters? — 18-Electron Rule (or Wade's Rules for clusters)

28. Which of the following metals is LEAST likely to form stable, isolable carbonyl clusters? — Copper

29. Which of the following is a characteristic structural motif in certain metal halide clusters? — Metal octahedra sharing edges or vertices

30. What is the general formula for a simple metal carbonyl M(CO)n where M is a transition metal? — M(CO)n

31. In metal cluster chemistry, the term 'ligand' most commonly refers to: — Atoms or molecules bonded to the metal atoms

32. The 'jelly roll' structure is observed in which type of metal cluster? — Metal halide clusters

33. A cluster with a 'closo' structure according to Wade's Rules would have how many vertices in its polyhedral cage? — n

34. Metal halide clusters typically involve metal atoms bonded to: — Halogen atoms

35. Which of the following is a characteristic feature of metal halide clusters? — Often form extended solid-state structures

36. Which of the following is a key characteristic of metal clusters that distinguishes them from simple coordination compounds? — Direct metal-metal bonding and delocalized electron systems

37. The metal-metal bonds in clusters are typically: — Covalent, often delocalized

38. The 'delta-bond' in metal clusters arises from the overlap of: — d-orbitals

39. The term 'cage compounds' in metal cluster chemistry refers to: — Structures where metal atoms form a discrete, enclosed framework

40. Metal halide clusters of the type [M6X12]n+ often feature: — Edge-sharing octahedral metal cores

41. In halide clusters like [Nb6Cl12]2+, the metal atoms are typically in what coordination environment concerning the halides? — Edge-bridging halides

42. What is the typical geometry of a 'butterfly' metal cluster? — Planar with four metal atoms forming a rhombus

43. The 'skeletal electron count' (SEC) in metal clusters is crucial for determining: — The geometric structure (polyhedral shape)

44. The reactivity of metal clusters is often influenced by: — All of the above

45. The term 'polyhedral skeletal electron count' (PSE) is synonymous with: — The skeletal electron count (SEC)

46. The '18-electron rule' for mononuclear complexes is adapted for clusters by considering: — The total number of valence electrons from all metal atoms and ligands

47. The catalytic activity of metal clusters is often attributed to: — All of the above

48. What is the significance of the 'Wade's Rules' in predicting cluster geometry? — They relate the number of skeletal electrons to the polyhedral shape

49. Which type of metal halide cluster is characterized by a linear arrangement of metal atoms, each bonded to six halide ligands? — Triple-bridged linear chains

Cages and clusters: metal cluster chemistry including metal carbonyls and halide type clusters - One Line Questions