Hi,

Question

How do you know how many ligands a metal ion needs to form a complex ion?

So for example, with (Fe(H20)6)2+, how am I supposed to know that the Fe needs 6 H20's, rather than 4?

Thank you!

Answer 1

http://chem.libretexts.org/Core/Inorganic_Chemistry/Coordination_Chemistry/Properties_of_Coordination_Compounds/What_is_a_Complex_Ion%3F

Start with the d level electrons in iron.