Charge & Spin Ordering: Explained & Bond Lengths

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Discussion Overview

The discussion centers on the concepts of charge and spin ordering, exploring their differences and relationships. It also addresses how bond lengths are affected by the oxidation states of elements, specifically comparing Te4+ and Te5+ when bonded to oxygen. Additionally, there are inquiries about the ground state spins of niobium ions and their magnetic properties.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant seeks clarification on the differences and relationships between charge and spin ordering, expressing confusion about the concepts.
  • Another participant provides an example of Holmium metal, describing its helicomagnetic properties where charge density is homogeneous but spin order is complex.
  • It is suggested that higher oxidation states typically result in shorter bond lengths due to increased Coulomb interactions, though the potential for unequal bond lengths depends on specific bonding details, such as Jahn-Teller distortions.
  • A participant questions the ground state spins of niobium ions, noting the difference between Nb5+ being d0 and diamagnetic, while Nb4+ is d1 and paramagnetic.
  • Another participant explains that Nb5+ has all valence electrons removed, resulting in filled shells and diamagnetism, while Nb4+ retains one d-electron, leading to paramagnetism.

Areas of Agreement / Disagreement

The discussion includes multiple viewpoints regarding charge and spin ordering, as well as the effects of oxidation states on bond lengths. There is no consensus on the relationships or implications of these concepts, and participants express varying levels of understanding and inquiry.

Contextual Notes

Some assumptions about the nature of charge and spin ordering, as well as the specifics of bond length variations, remain unaddressed. The discussion does not resolve the complexities of these relationships or the implications of Jahn-Teller distortions.

Who May Find This Useful

This discussion may be of interest to those studying solid-state physics, chemistry, or materials science, particularly in the context of magnetic properties and bonding in transition metals.

marie2010
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hi,
Can someone explain to me the difference between charge and spin ordering? How are they different and how are they related? I am very confused.
Also, how are the bond lengths affected if an element is in 4+ as opposed to 5+ (e.g. Te4+ or Te5+ bonded to 6 oxygens). Are they shorter/longer, unequal distribution.
Can someone please comment.
Thanks.
 
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Maybe an example is helpful: E. g. Holmium metal is a helicomagnet. Although the charge density at each Holmium atom is equal, the spin of the electrons at different sites points in different directions. Specifically, when moving along some axis in the crystal the spin rotates tracing out a helix in space. So while charge order is homogeneous, the spin order is quite complex.
To the second question: Typically, the higher the charge of the central atom, the shorter the bonds (due to the increased Coulomb interaction). Whether the bond length become unequal depends on details in the bonding and cannot be answered generally. A common cause for unequal bond length is a Jahn Teller distortion.
 
how to calculate ground state spins of odd-odd nucleus in the nilsson diagrams
 
Thank you for replying. Can you please help me understand the following:
How come Nb5+ is d0 and diamagnetic, but Nb4+ is d1. I cannot see it.
Thanks in advance.
 
Niob is in the fifth secondary group in the periodic system, i.e. it has 5 valence electrons (3 d- electrons and 2 s electrons). In Nb(V) you removed all of them leaving only filled shells, hence it is diamagnetic. In Nb(IV) one d-electron is left. Hence it is paramagnetic.
 
Thank you. I got it now.
 

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