DOC PREVIEW
ISU CHE 141 - Spectrochemical Series
Type Lecture Note
Pages 4

This preview shows page 1 out of 4 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 4 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 4 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

CHE 141 1st Edition Lecture 25 Current LectureCrystal Field Splitting Magnetism- Magnetic properties depend on the number of unpaired electrons in the valence shell d orbitals- Diamagnetic a substance with no unpaired electrons that is weakly repelled by a magnetic field- Paramagnetic a substance with unpaired electrons that is attracted to a magneticfield- The more unpaired electrons, the more paramagnetic the ion- Crystal field splitting affects the number of unpaired electrons in the d orbital thus influences magnetism- Which is more likely to be a paramagnetic in an octahedral crystal field, high spin Fe3+ or low spin Fe#+o Fe3+:[Ar]3d^5o In an octahedral crystal field high spin Fe3+ has 5 unpaired electrons and low spin Fe3+ has one unpaired electrono The more unpaired electrons the more paramagnetic the ion thus high spin Fe3+ is more likely to be paramagneticCrystal Field Splitting: High Spin or Low Spin?- To decide whether a complex is high or low spin, you can usually follow these rules:These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Delta>P, the more likely the metal ion is to be in a low spin stateo Delta <P, the more likely the metal ion is to be in a high spin stateo Higher metal oxidation state draws ligands closer, causing greater repulsion with the d-orbitals and therefore a larger delta, thus as the charge on the metal ion increases, delta increases (metals with high oxidation states are likely to be low spin)o The further up the spectrochemical series, the higher the field strength of the ligands, the larger the delta O Strong field ligands (NH3, en, CN-) usually produce low spin complexes delta >P Weak field ligands (F-,OH-,H2O) usually produce high spin complexes delta<Po Because there are only 4 ligands in a tetrahedral complex, delta is usually smallerthan P, so tetrahedral complexes are normally high spino 5th or 6th row transition metals tent to be low spin as their 4d and 5d orbitals extend farther out from the nucleus, interacting more strongly with the electron lone pairs on the ligands, leading to greater deltao high metal oxidation statehigh spino strong field ligandlow spino weak field ligandhigh spino tetrahedral complexusually high spino 5th and 6th row TM low spinApplications of Coordination Compounds- in a coordination compound the ligands make the metals chemically reactive and biologically available- coordination compounds perform many important functions in nature and industry suchas sequestering agents, chemical analysis, coloring agents, catalysts, biomoleculesSequestering Agents- EDTA4- is a hexadentate sequestering agent that has lone pairs on six different donor atoms thus can form very stable metal complexes- [Ca(EDTA)]2- is used to treat victims of heavy metal poisoning- the lead complex (Kf=2x10^18) is more stable so the lead displaces the calcium- the body excretes the stable lead complex and leaves behind the calcium, which is nontoxicChemical Analysis- We can utilize the selective binding of certain ligands and the ability of TMs to form colored compounds to analyze a sample- The SCN- ligand forms [Fe(SCN)]2+ thiocyanatoiron(II) (blood red) in the presence of Fe3+ and [Co(SCN)4]2- tetrathiocyanatocobaltate(II) (bright blue) in the presence of Co 2+Coloring Agents- Rubies are crystalline Al2O3 (corundum), which is colorless. The red color comes from around 1% of Al3+ ions being replaced by Cr3+- Emeralds are crystalline [Be3Al2(SiO3)6]. Pure Beryl is colorless but green emeralds contain around 1% Cr3+- Rubies have stronger crystal field than emeralds, thus rubies have greater splitting of thed-orbitals so absorb a different color of light than emeraldsCatalysts- Coordination compounds consisting of a metal center coordinated to organtic ligands areparticularly important in homogeneous catalysis- Organic ligand bound to a metal via heteroatom (atom that is not Cor H) such as O or N still considered a coordination compound- If organic ligand bound with a M-C bond, this is known as an organometallic compound- TiCl3 is the main catalyst used in industrial production of polypropylene, which has an annual global demand of around 45.1 million metric tons, equating to turnover of $65


View Full Document

ISU CHE 141 - Spectrochemical Series

Type: Lecture Note
Pages: 4
Documents in this Course
Load more
Download Spectrochemical Series
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Spectrochemical Series and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Spectrochemical Series 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?