Atomic Radii of Fe and Ni: Which to Trust?

In summary, it is difficult to determine which ionic radius to use when calculating plane density for metals because they have different oxidation numbers.
  • #1
Dell
590
0
for the calculations in one of my homework questions, i need to use the atomic radii of Fe and Ni, the problem is that every site i come across gives me different values

Fe
wikipedia 126pm
physlink 1.72A
chemicool 140pm


how do i know which one to "trust" ?
 
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  • #2
Is that zero valent iron and nickel or one of their ions?

The ionic radii for ions are a function of their coordination number and oxidation #.
 
  • #3
I think I have seen such data on IUPAC site, even if it is not correct, source sounds as reliably as possible.

No idea what is the definition of atomic radius, could be differences can be attributed to different understanding of what the atomic radius is.

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  • #4
It is likely the atomic radius in gas phase. Putting a metal atom in a metal lattice can change the radius as well.
 
  • #5
chemisttree said:
It is likely the atomic radius in gas phase. Putting a metal atom in a metal lattice can change the radius as well.

That's more or less what I am aiming at - depending on the way you want it, you will get different numbers. Even in the gas phase it is not obvious to me what 'size' means, as atoms don't end abruptly :wink:

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  • #6
im really confused,, the question goes like this

find the plane density for the plane [1 1 1] of the following:

iron (BCC)
nickel (FCC)

for [111] i know that
BCC- R=sqrt(3)/4*a
FCC- R=sqrt(2)/4*a

PD=n/A

BCC[111]- PD=sqrt(3)/(16*R^2)
FCC[111]- PD=sqrt(3)/(6*R^2)now all i need to do is find the CORRECT radius to use, i used
FE 126pm
Ni 124 pm

and got

PD(Fe)= 6.818*10^-6 [atoms/pm^2]
PD(Ni)= 1.877*10^-5 [atoms/pm^2]

but i don't know if that's right
 

1. What is atomic radius and why is it important?

Atomic radius is the distance from the nucleus of an atom to its outermost electron. It is an important measure because it can give insight into an atom's size, chemical and physical properties, and its reactivity with other atoms.

2. How is atomic radius determined for Fe and Ni?

Atomic radius is typically measured using X-ray crystallography or spectroscopy techniques. For Fe and Ni, it is determined by measuring the distance between the nuclei of two atoms when they are bonded together.

3. What are the reported atomic radii for Fe and Ni?

The reported atomic radii for Fe and Ni can vary depending on the source. Generally, the atomic radius for Fe is reported to be around 125 pm, while the atomic radius for Ni is reported to be around 135 pm.

4. Which atomic radius measurement should be trusted for Fe and Ni?

Due to variations in measurement techniques and sources, it can be difficult to determine which atomic radius measurement should be trusted for Fe and Ni. It is important to consider the source and method of measurement when comparing atomic radii.

5. How can atomic radii data for Fe and Ni be useful in scientific research?

Atomic radii data for Fe and Ni can be useful in many areas of scientific research, such as in understanding chemical bonding, predicting chemical reactions, and determining the properties and behavior of materials. It can also be helpful in identifying trends and patterns in the periodic table.

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