Questions tagged [crystal-structure]

In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid.

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407 views

Simple/ Primitive Tetragonal Bravais Lattice [closed]

Are there any elements which exhibit the Simple(Primitive) Tetragonal Bravais Lattice?
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What is the modern hardware/supermarket term for 'laundry bluing'?

I want to make this amazing paper Crystal Tree with my kids. One of the ingredients is laundry bluing. It is described thus: The magic crystals that are left behind are a combination of the Mrs. ...
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Ice Crystal Matrix measurements of H2O molecules?

I want a mathematically generated 3D STL copy of this image, however it's represent algorithmically. If I do all the H2O's as individual pieces with female connections prepared for chopped bike ...
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How to make pyramid-shaped NaCl salt crystals

I'm attempting to make sea salt pyramids like the one below. I understand this needs to be evaporated at a reasonable speed to stop the crystals forming a cube, as the when formed quickly, the edges ...
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How dried up detergent water led to precipitation of snowflake like shapes?

I forgot to drain the water off the bucket (after cleaning stain from a piece of clothing with detergent) and left it for few days. After few days when I needed it back, I found these glittery very ...
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Greater bond distance for silicon diamond structure than for carbon diamond structure?

In the silicon diamond structure the bond distance is about two times the bond distance of the carbon diamond structure. Is this caused only by the greater dimension of $\mathrm{Si}$ atoms with ...
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Image of crystal structure

Is there any websites or resources where I can get a good image of a certain crystal structure? In my case I'm looking for lead(II) tungstate $\ce{PbWO4}$ and I can't find a vivid graphic on google (...
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Finding the percent void of the crystalline structure of NaCl [closed]

Find the percent of void in the crystal structure of $\ce{NaCl}$. I am trying to calculate the percent void of the packing structure of $\ce{NaCl}$. Let's denote radius of anion as $r$, radius of ...
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How to visualize a crystal from a unit cell PDB and how to draw the unit cell's axes? [closed]

I am looking at the following PDB experimental data: Length (Å) Angle (°) a = 155.72 α = 90.00 b = 155.72 β = 90.00 c = 106.16 γ = 120.00 I find it hard to ...
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Can I supercool and solidify a liquid multiple times?

Let's say that I supercool a bottle of beer and then tap it so it freezes and solidifies. If I were to allow the frozen beer to melt completely, and then freeze the same bottle again, would it still ...
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Local resolution of a crystal structure in PDB File (protein data bank)

I am wondering if it is possible to find the local resolution of a crystal structure. Usually, the resolution of the PDB is assigned the resolution of the highest resolved part of the protein/nucleic ...
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Sense of radii quotient to determine coordination number in crystals?

Every common textbook explains the method of the radii quotient between the cation and anion of a selected salt to determine to coordination number(s) in that salt. For example deduce "Inorganic ...
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What system of nomenclature can I use to indicate the positions of specific kinds of atoms of a surface reconstruction?

I was reading a journal based on SiC reconstructions, and they seem to mention that every dangling bond in the $(1\times 1)$ unreconstructed Si face or the $(0001)$ direction bonds up with a Si adatom ...
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116 views

Generating PDB file from electron density without force field minimization

Is there a step-by-step tutorial on how to generate a PDB file from an electron density file (*.ccp4)? For my current project, I am trying to take some statistics ...
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442 views

Metallic Bonding

Since in metallic bonding, metals form ions and are surrounded by delocalized electrons, does that mean metal atoms always react in this ionised state? Can metal atoms lose valence electrons (like $\...
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Computational determination of unique adosrption sites

I'm not sure it's a chemistry question or physics question or math question. Since I'm active on this site, maybe someone here can point me in the right direction. I'm trying to enumerate all the ...
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Why shape of diamond is like diamond?

I know that in diamond carbon atoms occur in 3d geometry but i want to ask that why it is in shape of diamond not like some other 3d geometrical shape like cube or cuboid?
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956 views

What is the Difference between Menthol Crystal and Menthol Powder?

I want to buy menthol powder from a chemical supplier but he is selling menthol crystal at half price of menthol powder (he says manufacturing process is the difference) so I am really confused what ...
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How can you inhibit crystallisation of hot superconcentrated magnesium sulphate [closed]

I’m trying to create a gel like solution of primarily magnesium sulphate heptahydrate or Epsom salt and water. It’s simple to create a hot super concentrated solution but when it cools it’s obviously ...
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Formula of the compound based on occupancy of lattice voids

Atom of element $\ce{B}$ forms HCP lattice and those of the element $\ce{A}$ occupy 2/3rd of tetrahedral voids. What is the formula of the compound formed by the elements $\ce{A}$ and $\ce{B}$? My ...
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Can you heat Bismuth crystals to reset the oxide layer for new colors?

I'd like to get a bismuth crystal with small structures and deep blue colors for a ring I want to make. I can find these properties in different crystals online but never together. Can I just take a ...
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What is the crystal structure for a crystal where the ratio of the squares of the angle peaks is 0.825?

I followed this and it gives an example of how to identify a crystal structure using XRD data. I have an unknown alkali halide where two peaks were found at $2\theta =25.66$ and $2\theta = 28.3$. I ...
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What can be concluded from two different values for the interplanar distance between planes of atoms in an X-Ray diffraction experiment?

I analyzed an unknown Alkali Halide crystal using x-rays from a copper source. I need to find the d-spacing for this crystal, i.e. the interplanar distance between planes of atoms. I found my $K_\...
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How do I calculate lattice points per unit volume? [duplicate]

My professor was explaining simple cubic, body centered cubic, and face centered cubic lattices and I didn't quite understand the calculations below: Simple Cubic: $8 \cdot 1/8 = 1$ lattice point per ...
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1answer
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Calculating nearest neighbor distances

For cubic materials, there are equations in which to calculate nearest neighbor (NN), second nearest neighbor, etc. Can this be done with tetragonal crystal structures? I want to calculate NN, 2NN, ...
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Identifying a Positive or Neutral Ligand Inside Coordination Sphere?

There are some coordination compounds like $\ce{Na2[Fe(CN)5NO]}$, where ligands like $\ce{NO}$ are used which exist as both $\ce{NO+}$ (nitrosonium ion) and $\ce{NO^.}$ (neutral nitrosyl). How to ...
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To what extent are the radius ratio rules valid for predicting the crystal structure of an ionic compound?

The ionic radii of $\ce{Ba^2+}$ and $\ce{O^2-}$ in barium oxide are $\pu{135pm}$ and $\pu{140pm}$, respectively. The ratio of the radius of $\ce{Ba^2+}$ to $\ce{O^2-}$ is approximately $0.964$. ...
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Finding $c$ with Dulong-Petit law on non-molecular substance

The Wikipedia article states the Dulong-Petit law as follows: $$c=\frac{3R}M$$ $c$ is specific heat capacity $[\mathrm{\frac J{kg\; K}}]$ and $R$ the gas constant. $M$ is the molar mass in [g/mole], ...
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Why we don't talk about unit cells in hcp/fcc structures?

I'm studying basics of Solid State Chemistry from this source. So there are 14 types of Bravais crystal lattices (Primitive + Centered) in 3D. Every solid in this universe is made by the unit cells ...
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Miller Indices: How to deal with some weird(-ish) cases?

I've recently been doing a spot of self-learning (Crystallography), and some of the examples provided in the Wikipedia article for Miller Indices have stumped me. I can't for the world figure out how ...
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Calculating the theoretical Density of a Lithium oxide

I am trying to calculate the theoretical density for lithium oxide using the following formula $$\rho= \frac{n^{'}\sum M_c+\sum M_A}{V_c N_{AV}}$$ where $n^{'}$ is the number of formula units in unit ...
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Physical meaning of thermal parameters dimension (Ų)

In single-crystal x-ray crystallography both isotropic and anisotropic displacement parameters $U_{ij}$ of thermal ellipsoids have dimension of square angstrom ($Å^2$) as follows from the definition ...
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Post-synthetic Anisotropic Wet-Chemical Etching of Colloidal Sodalite ZIF Crystals

It's well known that Metal-organic Frameworks can be made by attaching inorganic metal ions to organic linkers via strong chemical bonds, ZIF-67 is one of this big family which could be prepared by ...
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Fractal patterns on water

I stored water in a bucket (of aluminium probably), and some random fractal-like patterns are formed on the water: See here for some more pictures. Why this happened? I'm unable to reproduce it. ...
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What does stepped Ni(111) surface mean?

I think (111) surface refers to a flat surface of atoms that intersect with x,y,z axis at 1.
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Use of geometry index for the determination of coordination environment

Geometry index $\tau$ is supposed to resolve proper geometry for coordination numbers (C.N.) 4 and 5 based on its extreme values ($0$ or $1$). There is also a web app Geom which handles both cases for ...
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What causes the stairstep structure in bismuth crystals?

I've been interested in bismuth crystallization since I found out they existed, but have a question on their formation. According to Wikipedia, the stair-step structure of bismuth crystals is "the ...
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Number of atoms per unit cell

I don't understand the concept of unit cell and the number of atoms per unit cell in a cubic lattice also the calculations for the number of atoms. For example in the $\ce{fcc}$ lattice, number of ...
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What determines how much water of crystallisation a salt has?

Is there any reason behind the number of water of crystallisation? For example, $\ce{LiCl.2H2O}$ has two waters of crystallisation, and $\ce{MgCl2.8H2O}$ has 8 waters of crystallisation. Why does $\...
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How to get Jmol to automatically determine and display bond order?

Some molecule file formats do not detail bond order and when I open these formats in Jmol implied (by the valency, of course) double bonds are not shown as double bonds but rather as single bonds. Is ...
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Trioxane fuel tablet recrystalization

I had a bunch of old military trioxane fuel tablets. I decided to open all of the packets, maybe a dozen, and place the contents in an empty tin coffee can with a plastic lid. I put the can in a ...
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What is the reason for isotropy in amorphous solids?

In my book, it's been mentioned that crystalline solids are anisotropic whereas amorphous solids are isotropic in nature. The reason for these has been explained (with a diagram) as: Crystalline ...
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1answer
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Why is the empirical formula of sodium chloride NaCl? [duplicate]

Since we know in sodium chloride crystal sodium ions are surrounded by $6$ chloride ions and each chloride ions are again bonded to $6$ sodium ions. What I want to know is that on what basis empirical ...
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Is this an aluminum screw dislocation?

Is this an aluminum screw dislocation? https://youtu.be/zbUPjHHml1E?t=55s I have heard of zinc pest which looks similar.
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Why is the buckminsterfullerene the purest form of carbon?

Other websites say that $\ce{C60}$ doesn't have surface bonds that are attracted by other atoms as in graphite and diamond. I understand that graphite may be attracted by other atoms because of its ...
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What is the volume occupied by the atoms and the edge length in these cubic lattices?

Consider a cubic unit cell of crystal that is composed of a single kind of atom. By placing atoms at every corner of the cube, a simple cubic lattice is formed. Assume that the atoms are perfect hard ...
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1answer
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Schottky Defect in AB2 type crystals

Are there any examples of Schottky defect in ${\ce{AB_2}} $ type crystals. Does Schottky defect require that the cation and anion be of equal size? According to me it is not necessary that the two ...
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Limiting radius ratio

I recently came across this question while studying Solid State. The coordination no. of [Ni(CN)4]2- is 4 as Ni is bonded to 4 CNs and is planar in structure.Hence its Limiting Radius Ratio must be ...
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How to calculate the height of an hcp lattice?

A hexagonal closed packing (hcp) unit cell has an ABAB type of packing. For calculating the packing fraction we require the volume of the unit cell. Volume of hcp lattice = (Base area) $\cdot$ (...
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metallic bonding in transition metal sulfides

I searched on the internet but failed to find a clear solution for this question: Regarding transition metal sulfides like NiS or FeS, is there metallic bonding within their crystal structure? If ...

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