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orbitals are potentially π donors. These types of ligands tend to donate these electrons to the metal along with the σ bonding electrons, exhibiting stronger metal-ligand interactions and an effective decrease of Δ. Most halide ligands as well as OH are primary examples of π donor ligands.
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Ligands arranged on the left end of this spectrochemical series are generally regarded as weaker ligands and cannot cause forcible pairing of electrons within the 3d level, and thus form outer orbital octahedral complexes that are
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In general, it is not possible to say whether a given ligand will exert a strong field or a weak field on a given metal ion. However, when we consider the metal ion, the following two useful trends are observed:
229:. On the other hand, ligands lying at the right end are stronger ligands and form inner orbital octahedral complexes after forcible pairing of electrons within 3d level and hence are called low spin ligands.
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However, it is known that "the spectrochemical series is essentially backwards from what it should be for a reasonable prediction based on the assumptions of crystal field theory." This deviation from
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The order of the spectrochemical series can be derived from the understanding that ligands are frequently classified by their donor or acceptor abilities. Some, like NH
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The spectrochemical series was first proposed in 1938 based on the results of absorption spectra of cobalt complexes.
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can also be arranged in order of increasing Δ, and this order is largely independent of the identity of the ligand.
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highlights the weakness of crystal field theory's assumption of purely ionic bonds between metal and ligand.
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Fifth
Edition. Boston: Houghton Mifflin Company, 2005. Pages 550-551 and 957-964.
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listing of ligands from small Δ to large Δ is given below. (For a table, see the
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has a stronger effect than ammonia, generating a larger ligand field split, Δ.
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List of ligands in coordination compounds topic of
Inorganic chemistry
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4th edition, HarperCollins
College Publishers, 1993. Pages 405-408.
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Mn < Ni < Co < Fe < V < Fe < Cr < V < Co
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ordered by ligand "strength", and a list of metal ions based on
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Inorganic
Chemistry: Principles of Structure and Reactivity
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3rd edition, Oxford
University Press, 2001. Pages: 227-236.
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orbitals of suitable energy, there is the possibility of
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James E. Huheey, Ellen A. Keiter, and
Richard L. Keiter
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http://science.marshall.edu/castella/chm448/chap11.pdf
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355:"Absorption Spectra of Co-ordination Compounds. I."
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312: – Term in the chemistry of transition metals
426:(4th ed.). Prentice Hall. pp. 395–396.
296:Δ increases with increasing oxidation number, and
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451:"The Spectrochemical Series – Every Science"
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263:When ligands have vacant π* and
214:Strong field ligands: CO, CN, NH
41:ligand-field splitting parameter
329:D. F. Shriver and P. W. Atkins
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386:"B.2. Spectrochemical Series"
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255:Ligands that have occupied
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299:Δ increases down a group.
476:Coordination chemistry
76:spectrochemical series
21:spectrochemical series
207:Weak field ligands: H
390:Chemistry LibreTexts
358:Bull. Chem. Soc. Jpn
353:R. Tsuchida (1938).
310:Nephelauxetic effect
235:crystal field theory
53:crystal field theory
471:Inorganic chemistry
424:Inorganic Chemistry
371:10.1246/bcsj.13.388
331:Inorganic Chemistry
324:Chemical Principles
322:Zumdahl, Steven S.
188:(N–bonded) < PPh
57:magnetic properties
45:ligand field theory
194:Triphenylphosphine
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317:References
281:metal ions
74:A partial
61:spin state
37:d orbitals
227:high spin
169:< en (
158:< py (
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160:pyridine
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164:NH
156:CN
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140:H
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121:F
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95:S
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