Hello, my name is Walter Unglaub. And this is what is the spectrochemical series. In chemistry and in crystal theory, the spectrochemical series is actually a set of two lists that describes ligands, which are molecules or ions that bind to essential metal atoms. So, the first list or series is a series of those ligands. And as I already mentioned these ligands are ions, o.k. They can be molecules, so it doesn't have to be a single atom. But the point is they are ions that bind to a metal atom to form the ligand molecule. So, how are these ligands ordered? They're ordered in increasing delta. Where delta is a symbol for the ligand field splitting parameter. What this describes is the energy difference between the D orbitals. Which are a type of electron orbital in the atoms. So, as this energy difference in the D orbitals of a given ligand increases, we have our ordering from a weaker ligand to a stronger ligand. As an example, we can consider N-three minus, this is nitrogen ion. And this is a weaker ligand than the fluorine ion, F-minus. Which is a weaker ligand than the OH minus ion. So, we see that going from left to right, we're increasing the energy difference in D orbitals. So the delta, the ligand field splitting parameter is larger towards the right. So the other list, the first list being the series of ligands, is the list or series of those metal atoms to which the ligands bind. So, the essential metal atoms are also going to be ordered in increasing value of delta. And the increasing energy difference in the D orbitals specifically. So, as an example, we have cobalt two plus, which is going to be weaker than iron two plus. Which is going to be weaker than vanadium two plus. So, as we move from left to right, we form our ordered list, our series of essential metal atoms to which these ligands can bind to. And again, this list will depend on this parameter delta. This comprises of what we call in chemistry and in crystal theory, the spectrochemical series. My name is Walter Unglaub, and this is what is the spectrochemical series.