Explanations 
Textbooks 
Flashcards 
91影视 AI 
Notes 
Study Plans 
Study Sets 
Find a degree 
Magazine Chapter 2: Problem 225
Which of the following is non-existent? (a) \(\mathrm{AlF}_{6}^{3-}\) \(\square\) (b) \(\mathrm{CoF}_{6}^{3-}\) (c) \(\mathrm{BF}_{6}^{3-}\) \(\square\) (d) \(\mathrm{SiF}_{6}^{2-}\)
Short Answer
Expert verified
Option (c) \(\mathrm{BF}_{6}^{3-}\) is non-existent.
Step by step solution
01
Understanding Ligand and Central Atom Compatibility
To determine the existence of a complex ion, examine both the central atom and the ligands. The central atom must be capable of expanding its octet to accommodate the ligands. This typically involves having d-orbitals available for bonding with the ligands. Analyze each option to see if this condition is satisfied.
02
Analyze \\(\mathrm{AlF}_{6}^{3-}\\)
Aluminum (Al) can expand its octet as it has empty 3d orbitals available for bonding. Therefore, \(\mathrm{AlF}_{6}^{3-}\) is potentially stable.
03
Analyze \\(\mathrm{CoF}_{6}^{3-}\\)
Cobalt (Co) is a transition metal capable of using its d-orbitals for bonding with fluoride ions. Thus, \(\mathrm{CoF}_{6}^{3-}\) can exist.
04
Analyze \\(\mathrm{BF}_{6}^{3-}\\)
Boron (B) typically forms compounds where it completes an octet. Boron does not have available d-orbitals to expand beyond its octet. Therefore, it cannot form a hexafluoride ion, making \(\mathrm{BF}_{6}^{3-}\) non-existent.
05
Analyze \\(\mathrm{SiF}_{6}^{2-}\\)
Silicon (Si), like many Group 14 elements, can expand its octet due to the availability of d-orbitals. Therefore, \(\mathrm{SiF}_{6}^{2-}\) can exist.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91影视!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Ligand Compatibility
In chemistry, determining whether a complex ion can exist often begins with evaluating ligand compatibility. Ligands are ions or molecules that can donate a pair of electrons to form a coordinate bond with a central atom. Ligand compatibility is influenced by the size, charge, and electronic environment of the ligands.
For a successful interaction,
For a successful interaction,
- The ligands must be small enough to fit around the central atom without causing excessive steric hindrance.
- Ligands should also possess the appropriate charge or electronegativity to form a stable bond with the central atom.
- Consider if ligands prefer to bond with metals that can provide a stable electron arrangement.
Central Atom and d-orbitals
The ability of a central atom to form a complex ion is heavily dependent on its electron configuration, specifically the availability of d-orbitals.
Central atoms that can accommodate more than eight electrons must have open or available d-orbitals:
Central atoms that can accommodate more than eight electrons must have open or available d-orbitals:
- Transition metals, such as cobalt (\(\mathrm{Co}\)), naturally have these d-orbitals and use them for bonding, allowing them to form complex ions with various ligands.
- Main group elements may also expand their octet, provided they can utilize d-orbitals, such as in the case of aluminum (\(\mathrm{Al}\)) and silicon (\(\mathrm{Si}\)).
Octet Expansion
Octet expansion is a concept where certain atoms can accommodate more than eight electrons in their valence shell. This is usually possible because they have available d-orbitals.
Not all elements are capable of doing this, making octet expansion a crucial factor in complex ion formation:
Not all elements are capable of doing this, making octet expansion a crucial factor in complex ion formation:
- For example, silicon and aluminum can expand their octet using the 3d-orbitals to accommodate additional bonding electrons.
- Boron, however, lacks available d-orbitals. Thus, it cannot expand its octet, making structures like \(\mathrm{BF}_{6}^{3-}\) impossible.
Hexafluoride Ions
Hexafluoride ions are a type of complex ion characterized by the central atom's coordination with six fluoride ligands.
Their stability depends on several factors:
Their stability depends on several factors:
- Central atoms like cobalt (\(\mathrm{Co}\)) and silicon (\(\mathrm{Si}\)) that can expand their octet demonstrate the ability to form such complex ions, given they can accommodate six fluoride ions within their expanded valence shell.
- Fluoride ions, being small and highly electronegative, contribute to a robust electron cloud density around the central atom, aiding in the stability of the resulting complex.
