Formation and the shape of complex ions Flashcards
How are complex ions formed?
When one or more molecules or negatively charged ions bond to a central metal ion. These molecules or ions are called ligands
Define a ligand?
A molecule or ion that donates a pair of electrons to a central metal ion to form a coordinate bond or a dative covalent bond
What is a dative/coordinate bond?
A special kind of covalent bond where one of the bonded atom supplies both of the electrons in the shared pair
What is a coordination number?
Indicates the number of coordinate bonds attached to the central metal ion
How do you represent a complex ion?
- the complex ion is enclosed within square brackets with the overall charge on the outside of the brackets
What are the two types of ligand?
-monodentate
- bidentate
What is a monodentate ligand?
- A ligand that donates one pair of electrons to a central metal ion
What are all the monodentate ligands and their charges?
H20 = 0
NH3 = 0
Cl- = -1
CN- = -1
OH- = -1
What is a bidentate ligand?
- A ligand that is able to donate two lone pairs of electrons to a central metal ion, forming 2 coordinate bonds
What are the two bidentate ligands?
- 1,2 diaminoethane
- ethanedioate ion
Draw a complex ion with a bidentate ligand?
[CO(NH2CH2CH2NH2)3]3+
Draw a complex ion with a monodentate ligand?
[Cr(H20)6]
What does the shape of a complex ion depend on?
- it depends on the coordination number
What shapes do complex ions with a 6 coordination number form?
octrahedral
What shapes do complex ions with a 4 coordination number form?
- tetrahedral
- square planar
What are the shapes that 6 coordination complexes form?
- cis/trans isomerism
- optical isomerism
Describe cis trans isomers in octrahedral complexes
- cis = the molecules are 90 degrees apart
- trans = the molecules are 180 degrees apart
Draw cis/trans and optical isomers in [co(NH2Ch2CH2NH2)]3 2+
Describe optical isomerism in octrahedral complexes
- occurs in octrahedral complexes containing two or more bidentate ligands
- only cis isomers can form optical isomers
Describe tetrahedral complexes?
- 4 coordinate
- only form with chlorine due to its size
- does not exist in cis trans isomers
Draw cocl4 2-
Describe square planar complexes?
- 4 coordinate
- have cis/ trans isomers
Draw cis/trans isomers in cis platin?
What is the action of cis platin?
- an effective chemotherapy treatment
- attaches to DNA and prevents DNA from replicating
- has many side effects
What is the formula of cis platin?
Pt(NH3)2Cl2
