Coordination Chemistry Flashcards
A complex is a ____ ion surrounded by ____
metal
ligands
____ are atoms or molecules that have lone pairs of electrons or electron density that can interact with metal centres
Ligands
A complex ligand is a ____. A simple ligand is a ____.
molecule
atom
Ligands act as lewis ____.
Bases
Ligands have lone pairs which they can donate to a ____
metal center
the central atom in a complex is a ____ _____
metal ion
Metals centers act as lewis ___.
acids
Lewis bases ____ lone pairs
donate
Lewis acids ____ lone pairs
accept
Name two things that characterize complexes
- Variable oxidation states due to variable occupation of the d-shell of the metal
- Higher covalent character in the bonds between the ligand and transition metal compared to pretransition metals
Do metals centers and ligands form simple ionic lattices?
no
What are the bonds between a metal center and ligands called? (2 possible answers)
Coordinate covalent bonds
dative bonds
What is the general formula for a complex?
[MLn]^m+
Define coordination number
the number of ligands bound to M^x+
Ligands can be …? (anionic, neutral, cationic)
anionic or neutral
Are ligands monoatomic or polyatomic?
Trick question, the answer is both!
The name of ____ ligands ends in an “o”
anionic
Define denticity
the number of atoms on the ligand that are used to bind to a metal
What are the two ways a ligand can be polydentate (denticity >1)?
Chelation
bridging
Define chelating
when 2 or more atoms on the same ligand bind to the
same metal ion
Define bridging
when the same ligand binds to more than one metal ion
What is the shape formed for a coordination number of 6?
octahedral
What is the shape formed for a coordination number of 4?
square planar or tetrahedral
What is the shape formed for a coordination number of 5?
trigonal bipyramidal
square pyramidal
What is the shape formed for a coordination number of 2?
linear
What is the shape formed for a coordination number of 3?
trigonal planar
What are the two geometric isomers for square planar?
cis and trans
For anionic complexes the metal name should end with “___”
-ate
What is the difference between an coordinate covalent bond and a covalent bond?
In the coordinate covalent bond only the ligand is donating e- for sharing where as in a covalent bond both parties would put forth e- for sharing
What is a coordinated complex?
A complex that is associated with an ion
What symbol is used to denote bridging ligands?
µ (greek letter mu)
What is meant when it is said that a molecule is paramagnetic?
The molecule is attracted to an external magnetic field (paramagnetism is a result of unpaired e-)
What is meant when it is said that a molecule is diamagnetic?
The molecule is not attracted to (in fact it is slightly repeled) by an external magnetic field
(diamagnetism is a result of all e- being spin paired)
How many d orbitals have e- density between the axes and how many d orbitals have e- on the axes?
3 in between the axes
2 on the axes
The CF splitting energy _____(decreases/increases) as you go down periodic table
increases
In general, the higher the oxidation state the _____ (lesser/greater) the CF splitting energy
greater
An increase in the number of ligands and e- results in a greater e- repulsion between ligands and and metals so the CF splitting energy is ____(lower/higher)
higher
Which generally has a higher CF splitting an octehedral complex or a tetrahedral complex?
Octehedral
When does high spin occur?
At the point where there is the maximum number of unpaired e-
When does lowspin occur?
When e- are all paired in lower energy orbitals before the higher energy orbitals
In the crystal field theory ligands are treated as ____ ____
point charges
In the crystal field theory there is no overlap between ___ ___ and ____ ____
ligand orbitals and metal orbitals
Is low or high spin more favourable?
low spin is more favourable
