shapes of complex ions Flashcards
What is the most common shape?
Complex ions have a variety of different shapes, the most common is the octahedral shape.
What is significant about octahedral complexes?
Octahedral complexes have 6 coordinate bonds and the outer face of the shape forms an octahedron.
Four of the bonds lie in a plane with the remain two perpendicularly above and below the plane, all bond angles are 90 or 180 degrees.
What are some examples of octahedral complexes?
Water and ammonia as they are similar in sizes and the right size to fit six molecules around a metal ion.
How can we form octahedral bonds?
We can form octahedral bonds with multidentate ligands as well, for example [Ni(en)3]^2+
What shape do chloride ions form?
Chloride ions are larger than water or ammonia and we can only fit four of them around a metal ion so it means that chloride ions usually form a tetrahedral shape.
What is another configuration that can be made with the coordination number of 4?
Square planar shape.
What is another shape that we are likely to encounter?
The linear shape of [Ag(NH3)]^2+, it is formed when we use Tollen’s reagent.
[ H3N —— Ag ——— NH3]^+
What do complex ions consist of?
Consist of a transition metal ions surrounded by ligands which donate electron pairs.
What are some common ligands?
H2O, NH3, Cl^-
How many electrons do :
Monodentate ligands donate?
Polydentate ligands donate?
Mono: 1 pair of e-
Poly: multiple pairs of e- per molecule or ion
What is the coordination number for octahedral complexes?
6
What shape do complexes with a four-fold coordination have?
Tetrahedral or planar shape
How do you find the number of electron pairs ?
- find the central atom
- work out how many electrons there are on the central atom
- add 1 e for every atom the central atom is bonded to ( if looking for an ion take its charge into account)
- add up all the electrons and divide by 2 to get the number of electron pairs
- compare the number of electron pairs to the number of bonds to get lone pairs
