Atomic packing factor in body centred cubic

In this video, Parisa works through the calculation of the atomic packing factor (APF) for the body centred cubic (BCC) crystal structure.

[Blasphemykat]

That isn't the atomic packing factor. That's a lattice parameter in terms of atomic radius.

[valentinfinozzi]

For anyone that comes by:
APF = (number of atom volumes inside a cell) * (atom volume) / (volume of a cell)

So for FCC we got:
(number of atom volumes inside a cell) = 4
Its one eighth of a volume in each corner and half a volume in each face
(atom volume) = volume of a sphere of radius equal to the atomic radius (R)
(volume of a cell) = a^3
with a = (4/sqrt2)*R

That gives APF = .74

[aniketsaratkar]

That is bcc's atomic radius for cubic lattice
And atomic packing factor for it is, 0.68 according to my perception

[TheCarClinicAndHybrid]

"And that how you find a, a is the lattice perimeter which if cubed is the volume of the cell." i think saying "a" is the APF is misleading sort off.

[abmj]

You are a real godess (hoor from junnah)❤

[Lilz]

I dont catch the part "4r^2", is it found by dividing the diagonals into four parts, where atoms are touching, and the center of the central atom?

[nyaindathomas]

That is not atomic packing factor.You have shown the relationship between atomic radius and edge length of a BCC crystal structure.But meanwhile thanks for the video.

[AbdulqadirAjabsha]

Okkk... That's half through the problem and now actually we have to put the values in the formula of the APF @Parisa Najafi 😅 ..though it was helpful 😃

[ahmedal-doori]

This is edge length of a BCC unit cell. It isn't the APF, since more steps are needed to get it.
From the edge length, we can find the unit cell volume. Then, we divide the total atom volume by that.
Good video but it's a bit misleading...

[raeroal]

a is the side of the unit cell which you cube to get Vc (volume of unit cell). APF =Vs/Vc where Vs is volume of spheres. 2 atoms in BCC so 2 x vol of sphere. APF =0.68

[ahmedjasim]

Good description but not as in the title

[fahadnauman]

Thanks, i got it in the first time :)

[kumarvinayakmaurya]

I am Indian 🇮🇳.. U are very quite and lovely.

[shivansh]

i came here to do only HCP now i'm doing whole course again

[obeb]

i need a tutor like her <3 <3 <3

[roumanfirdous]

this is side of BCC not APF.... u hve tot do more to find APF

[FBcrayz]

Change the title please. This is not atomic packing factor. This is a lattice parameter in terms of atomic radius. Your title is misleading.

[abidullah]

Feel like some kinda angel teaching APF .. she talks like angel oh lord i fall in love