# What is Fcc: Definition and 53 Discussions

6. ### Reciprocal lattice for FCC and diffraction peaks

My issue is more with the steps to approach rather than the calculations. I was just wondering if someone could confirm my approach to be correct. As it asking for the reciprocal lattice of an FCC I assume this would mean I need to use the points on the BCC to calculate the geometrical...
7. ### Setting up an FCC lattice in a simulation

Greetings, for a Monte Carlo simulation of N hard spheres, I want to set up the initial configuration as a fcc lattice. I am thinking about how to do it most efficiently. Here is the lattice structure: The 3 lattice vectors, each one pointing to a different type of the 12 nearest neighbors...
8. ### How Many Atoms to Draw in an FCC Lattice Problem?

Homework Statement Homework EquationsThe Attempt at a Solution Attempted in the picture
9. ### Crystallography; from hcp to fcc

Homework Statement Three close-packed planes of atoms are stacked to form fcc lattice. The stacking sequence of the three planes can be altered to form the hexagonal close packed structure by sliding the third plane by the vector r over the second. If the planes in the fcc structure are all...
10. ### I FCC Structure Factor: Exploring Bragg's Diffraction

I tried to treat FCC lattice with a lattice constant a, as a monoatomic lattice. The reciprocal lattice is a BCC with a lattice constant 2pi/a. And the structure factor is 1. But I can treat FCC lattice with a lattice constant a, as a simple cubic lattice, with 4 atoms in each unit cell. As one...
11. ### Solid State Physics, FCC or BCC and why?

Homework Statement Based on sizes for Na(.97 Angstroms), Cs(1.67 Angstroms), and Cl(1.81 Angstroms), which lattice type would you expect for NaCl and CsCl and why? Homework Equations My equation for the hole size for a bcc is (4/sqrt(3))(radius)-2(radius), I assume you put in the radius of Cl...
12. ### Preferred Crystal Structure of Steel (BCC vs FCC)

What are the reasons behind the different microstructures of steel at different temperatures? I don't understand why steel at high temperatures (austenite phase) would favor an FCC crystal structure while steel at lower temperature (ferrite) would favor a BCC crystal structure.
13. ### Why is radio spectrum allocation based on archaic models?

The FCC's propagation models for the FM broadcast band seem grotesquely inaccurate in some places, where stations can be received that the models say are absolutely out of range. I'm not even talking about DX conditions like ducting or skip, I'm talking about baseline. When I lived in...
14. ### The energy dispersion relation for sc, bcc and fcc?

Homework Statement I need to calculate the energy dispersion relation in the tight binding for simple cubic, base centered cubic and face centered cubic crystals. There are no values given, they just need the result depending on the lattice constant a. Homework Equations E (k) = alpha + beta *...
15. ### Why is the volume of FCC and BCC different in reciprocal space?

Taken from http://dao.mit.edu/8.231/BZandRL.pdf BCC In real space, it has a simple cubic lattice with one basis in the centre. Total number of atoms per unit cell = 2. Volume of primitive unit cell is then ##\frac{1}{2}a^3##. In reciprocal space, BCC becomes an FCC structure. It has a simple...
16. ### How Does Compression Transform FCC Lattice to BCC and Affect Miller Indices?

Homework Statement [/B] (a) Show Compression of FCC leads to BCC. (b) State rules for X-rays reflection in FCC. (c) What are the new Miller Indices after compression? Homework EquationsThe Attempt at a Solution Part(a)[/B] I'm quite confused as to what they mean by 'principal axes'. For an...
17. ### What can be done with the excess FCC flue gas

What can be done with the excess FCC flue gas from a fluid catalytic cracker
18. ### Do FCC Structures only have a CN of 12?

Hi all, Without first delving too deeply into the literature I wanted to ask if its is only permissible for FCC structures to have a coordination number of 12. In the case of lattice vacancies and/or distortion: wherein the atomic sites are slightly displaced; is there a kind of tolerence for...
19. ### Bulk Modulus and its derivative in a fcc lattice

The bulk modulus B = - V (∂P/∂V). At constant temperature the pressure is given by P= -∂U/∂V, where U is the total energy. We can write B in terms of the energy per particle u = U/N and volume per particle v = V/N : B = v...
20. ### News FCC Proposal to End Net Neutrality: Impacts and Implications

I'm very surprised that nobody has posted on the topic. The FCC is planing to kill net neutrality in everything but name; as a result, the internet could change in very fundamental ways. https://www.eff.org/issues/net-neutrality It is already affecting investments in startups...
21. ### Coordination number for fcc and NaCl

Why is the coordination number for fcc 12, but that in NaCl 6? NaCl crystallises in ccp (or fcc) lattice, then how is it possible?
22. ### Calculate the packing fraction of an FCC pyramid

Homework Statement Solids consist of a crystalline lattice of atoms-a unit cell that has a certain configuration of atoms that is repeated over and over. The picture that I can't post here, shows a pyramidal structure of metal spheres. The base is 8 spheres by 8 spheres with a height of 8...
23. ### Calculating 2θ for XRD Pattern of a FCC Lattice

Homework Statement A wavelength of 0.7107 Angstroms is used to analyse a polycrystalline sample with a known FCC lattice structure. The interplanar spacing of the first peak is 0.3 A. Calculate 2θ for the first 3 peaks on the XRD pattern. First 3 peaks occur at (111), (200) and (220)...
24. ### Dislocations in FCC and BCC iron due to C interstitials

I was just wondering why is it that the strengthening effect of interstitial carbon is different in FCC and BCC iron alloys. I can't figure this one out on my own so I thought I'd come to the place where the smart people hang out. Any opinions?
25. ### Fortran Fortran code for geometry of fcc

Hi friends . is there anybody here who can give me a fortran code for describing fcc lattice and give us the neighbours of each site and also which pay attention to periodic condition ? thank you for your help my friends.
26. ### Tight-Binding p-bands in fcc crystal, Ashcroft - Mermin book

Hi all, I'm trying to solve a problem in Ashcroft - Mermin "Solid State Physics", Chapter 10: The Tight-Binding Method, and need your help. Homework Statement In problem 2(c) it says: For a face-centered Bravais lattice with only nearest-neighbor \gamma_{ij} appreciable, show that the...
27. ### Powder XRD FCC spirals explanation

Hello All, I've been reading about XRD and found this picture online: http://en.wikipedia.org/wiki/File:Aluminumpowderpattern.png My question, which might be due to the lack of background as I'm an ECE guy, is why are the FCC lattice vectors depicted of Spirals whose minima lie on the...
28. ### Sources for Crystal Models (FCC, BCC, etc)?

I have been acquiring some nice molecular models of graphene, buckyballs, and things like the model below. http://www.indigo.com/images/product/172.jpg One thing I have not been able to find are crystal models with the different orientations like face-centered cubic, body-centered cubic...
29. M

### How Do I Calculate the Coordination Number for FCC?

When doing these coordination numbers, which atom do I consider? Am I supposed to use only one unit cell to determine the number? When counting the number of nearest neighbors, does it mean literally that only the number of atoms with the shortest distance can be counted, meaning you find the...
30. ### Upper limit of Miller indices of BCC and FCC crystals?

does anybody know the upper limit of the bcc and fcc metals like Fe, Cu, Ag? According to the fact that the planes with high (hkl) indices have small interplanar spacing d_hkl, the smallest spacing would be present. what is that? atomic diameter of a specifc metal?
31. ### The number of lattice point in FCC?

The number of lattice point in FCC? Hi, I am having a trouble to figure the number of lattie point in FCC structure out. My textbook said simple cubic has 1 lattice point, BCC has 2 points, and FCC has 4 points. However there is no further explanation or figures. I am a kind of understand...
32. ### Number of atoms in FCC gold cube with only the radius given

number of atoms in FCC gold cube with only the radius given! 1)it is given that the radius of a gold atom sphere is 144.2 pm, gold is packed in an FCC manner Give the ratio Ns/Nv as a function of L (gold cube side) and a parameter of FCC latice, knowing that Ns is the number of surface...
33. ### Number of atoms in FCC gold cube

Hello i need help in this question it is given that the radius of a gold atom sphere is 144.2 pm, gold is packed in an FCC manner Give the ratio Ns/Nv as a function of L (gold cube side) and a parameter of FCC latice, knowing that Ns is the number of surface atoms and Nv is the...
34. ### Why is fcc more ductile than bcc

HI all Why is fcc more ductile than bcc although bcc has greater number of slip planes than fcc?
35. ### News Net Neutrality, the FCC, and you wake up

http://www.csmonitor.com/Innovation/Horizons/2011/0923/Net-neutrality-rules-are-coming.-Here-s-why-they-matter" . and http://www.pcmag.com/article2/0,2817,2393442,00.asp" and and If you are alseep under a rock, this is a wake up call... Rhody... :frown:
36. ### Why in periodic table normally we have elements with FCC and HCP structure?

what is basic principle followed by atoms to arrange in basic structure?
37. ### Radial Distribution Function for HCP and FCC lattices

I was wondering, does anyone have any images that show the difference between the radial distribution functions for hcp and fcc lattices? I would be useful for reference purposes.
38. ### Why is HCP more common than FCC in elemental compositions?

This may be obvious but since the packing fraction for both hexagonal close packed and face centered cubic is the same (74% i believe) why is HCP more common in elemental compositions?
39. ### FCC Reciprocal to BCC: Proving Equation

Homework Statement The proof seems fairly straight forward, but after plugging in the primitive vectors to the equations for the reciprocal lattice vectors, I'm getting 2\pi\frac{\frac{a^2}{4}(x+y-z)}{\frac{a}{2}(y+z)\cdot(\frac{a^2}{4}(-x+y+z))} One proof I checked said that the bottom...
40. ### Distance between two layers in FCC unit cell

How is the distance between any two layers in a FCC unit cell equal to a/√3, where a is the edge length? I think it should be a/2 because the distance of a face centered atom from any 4 edges surrounding it is a/2. Can someone explain it geometrically?
41. ### Unit Cell - Linear Density - BCC & FCC

Unit Cell -- Linear Density -- BCC&FCC Homework Statement Calculate the linear density for the most densely packed directions in BCC and FCC. Note the difference in linear density. Note the difference in linear density. Homework Equations LD = #of atoms/length The Attempt at a...
42. ### Calculating the Schmid factor for an FCC single crystal

The problem said: "Determine the magnitude of the Schmid factor for an FCC single crystal oriented with its [100] direction parallel to the loading axis. " The Schmid factor is the "cos(\phi)*cos(\lambda)" term in the equation for resolved shear stress. I know that the slip planes...
43. ### Calculating the interplanar distance d111 for an FCC lattice

Homework Statement As a part of a lab report, I need to calculate the distance of the (111) planes of an FCC lattice made out of spheres with diameter D. Homework Equations The Attempt at a Solution The course assistant has given me the value of \frac{\sqrt{6}}{3}D. I can...
44. ### Miller Indices for FCC and BCC and XRay Diffraction Peaks

In my Physics lab, I'm doing X-Ray diffraction and attempting to determine the crystal structure of some common salts. To do this, I first need to determine the Miller Indices for the crystal structures that I'm considering. I can then match the location of peaks in X-Ray data (we're using...
45. ### Rhombohedral primitive cell on FCC

How do you determine a plane or a point on a crystal lattice when translated to a rhomboidal primitive cell. For example, rhombohedral primitive cell for an FCC is defined as: a_1 = 1/2 a*(x+y); a_2=1/2*a(y+z); a_3=1/2*a(z+x); If we have a plane, for example the 111 plane on an FCC, how...
46. ### May i know is structure such as bcc, fcc depends on how it process?

i study from some books that the properties of a materials depends on the structure of it, while the structure depends on how it being process..may i know what structure actually it means? i can't get its meaning..does it means the processing methods will influnce whether the materials will be...
47. ### Determine if BCC or FCC structure

Hey guys I've got a question and I am not sure how to go about answering it without looking up a table of characteristics of elements! Niobium has an atomic radius of 0.1430nm and a density of 8.57g/cm^3. Determine wheather it has an FCC or BCC crystal structure? Now i think you have to...
48. ### FCC Crystal Problem: Nearest Neighbors, Bond Angles & Packing Fraction

Homework Statement Write down the number of nearest neighbours in a FCC structure, calculate the angle between the bonds and the packing fraction. Homework Equations Literally don't know where to start! The Attempt at a Solution Very confused at the moment. Tried to look up...
49. ### Tension-Compression Asymmetry in FCC

Hello, FCC metals experience significant tension-compression asymmetry because of the comparatively limited number of slip systems that act under compression, compared to tension, right? Thanks, -scott
50. ### Calculating Planar Density for FCC {100}, {110}, {111}

HOw od you calculate the planar density for {100}, {110}, {111} for FCC?