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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690 views

What is the structure of N₅P₃?

What is the structure of the molecule $\ce{N5P3}$? $\ce{N5P3}$ is not documented online, so could anyone please comment on the structure of the molecule: How many ligands does each phosphorous atom ...
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Which gems can be prepared on a small scale basis?

I am interested to know the following: Which gems can be prepared at home (without sophisticated instruments)? What will be the quality (appearance) of the product for a certain method? I want these ...
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Confusion in unit cells of crystal system

Unit cells are divided into two main types Primitive Non-primitive Primitive includes simple cubic lattice whereas non-primitive includes fcc bcc end centered.. Among the seven types of crystal ...
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Crystallization of solutions and liquids

The process of crystallization of a liquid or any solute occurs when its concentration exceeds the maximum concentration which the solvent can carry or when the temperature drops below the freezing ...
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Create my own solar cells?

How would I grow my own and build functional solar cells? I've read and researched that they're mostly a crystal structure of something like silicon. I would assume I'd be able to grow my own crystals ...
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How do octahedral seed crystals yield polyhedral Cu₂O crystals?

In an article I am trying to understand, the following occurs: (summarized below) Synthesis of octahedral $\ce{Cu_2O}$ seeds:In a typical synthesis, 2.9946 g of $\ce{Cu(CH_3COO)_2}$ was dissolved ...
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1answer
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Smallest nearest neighbor distance among elements

Of all the elements in periodic table, which one has smallest nearest neighbor distance? I tried searching on net, but could not find any reference. My earlier guess was one which goes into FCC with ...
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1answer
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Normal Spinel and Inverse Spinel

According to my notes, octahedral site stabilization energy (OSSE), sterical effects and electronic effects in stability create a confusion in this theory. However, we are able to solve this problem ...
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1answer
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Overlapping oxygens in crystal structure — what's going on?

This is a screenshot of a portion of a metal organic framework (MOF). These are two oxygens of two NMP solvent molecules. What I am wondering is why they are so close and overlapping like this. I ...
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1answer
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How to rationalise the coordination number of CsCl versus NaCl?

Question: Suggest an explanation for the coordination number in the $\ce{CsCl}$ lattice being different from those in $\ce{NaCl}$. Standard answer: Caesium ion is larger than sodium ion, hence ...
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Is diamond an allotrope or polymorph of carbon?

Is diamond an allotrope or polymorph of carbon? When is something considered an allotrope vs a polymorph?
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How can you explain that the ratio of the densities of Ag and Au equals the ratio of their relative masses?

My book says that silver and gold both have the same face centered cubic structure and then asks to show and explain why the ratio of their densities equals the ratio of their relative masses. How can ...
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Why does Naphthalene turn into needle-shaped crystals by sublimation?

I wonder why crystals of Naphthalene are needle-shaped after sublimation. Googling the fact, I could only confirm that it is true but failed to find the reason. Could someone please shed some light as ...
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1answer
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Reduction and re-oxidation of TiO₂

I'm having a hard time finding data about an experiment that I know has been done a bunch of times: I have a sheet of single crystal rutile $\ce{TiO_{2}}$ (110) that I want to reduce to various $\ce{...
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Which theta should be taken from x-ray diffraction pattern for calculating Scherrer's equation?

We use Scherrer's equation to calculate crystalline size of a particle: $$d = \frac{Bλ}{β\cos{θ}}$$ But which theta should we take from the XRD pattern for this calculation? For example, the ...
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Would the detaching of dendrites from electrodes in a cell, result in the crystal dissolving back into the electrolyte?

Dendrites that form on the electrodes of cells shorten the cell's lifetime, and result in reduced capacity before the end of life. If the dendrites could be detached from the electrode, would they ...
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How are crystals formed from a gas?

In crystallization, crystals are formed from liquids by cooling. How can crystals be formed from a gas by cooling?
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What is burst nucleation? [closed]

Can you tell me what is a burst nucleation process, and how can it be used for synthesising uniform nanoparticles? Can you also provide (if possible) any links to papers or materials regarding ...
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What salts are/are not birefringent?

Is there a quick way to determine if a salt (or ionic compound in general) crystal should be birefringent from its formula without having to know/look up the crystal structure? When I'm looking for ...
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When we heat a borax crystal, why does it first expand and then contract?

In the borax bead test, we take a crystal of borax and then heat it. A small loop is made in the end of a platinum or nichrome wire (as used in the flame test) and heated in a Bunsen flame until ...
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How do copper sulphate and the like change crystal structure on adding water of hydration?

Copper sulphate, in its hydrated form, is crystalline, whereas the anhydrous form is amorphous. Gypsum has a similar story-- on heating the crystalline dihydrate we get an amorphous hemihydrate. (...
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Choice of doping elements in semiconductors

In a typical semiconducting material, we start with silicon (group IV) and introduce atoms of group V or group III depending on whether we are constructing an n- or p-type semiconductor respectively. ...
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Are these two space groups in a group–subgroup relationship?

Given two crystal space groups, how can one determine if they are in a group-subgroup relationship? The specific case at hand is P 21/m 2/m 2/a (aka P m m a, #51) and P m m 2 (#25), but knowing how to ...
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What is it about the relationship between the Fe²⁺ and Fe³⁺ in magnetite that makes it diamagnetic?

Hematite is composed of $\ce{Fe2O3}$, and is paramagnetic, whereas magnetite is $\ce{Fe3O4}$ and is diamagnetic. Magnetite's nature is due to the presence of both $\ce{Fe^{2+}}$ and $\ce{Fe^{3+}}$ (...
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Why are there no edge dislocations in a face-centered cubic (FCC) lattice?

In crystallography, we know that the Burgers vector is parallel to the dislocation direction in a screw dislocation, and perpendicular in a edge dislocation. Furthermore, I have in my lecture notes "...
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Is there a theory behind selecting elements that may be successful in potential superconductors?

Looking at something like $\ce{YBa2Cu3O7}$ which was one of the first cuprate superconductors to be discovered, I'm always curious how the selection of these substances as likely superconductors comes ...
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How is the electron “trapped in the crystal” in irradiated NaCl?

Pennsylvania State University provides irradiated $\ce{NaCl}$ (180,000 rads of gamma radiation) to teachers for a very entertaining demonstration. The salt is orange after irradiation. When it is ...
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How does NaCl maintain its crystalline structure?

My understanding is that $\mathrm{NaCl}$ is an ionic compound, in which $\mathrm{Cl}$ becomes (effectively) $\mathrm{Cl^-}$ and $\mathrm{Na}$ becomes $\mathrm{Na^+}$. So I understand why I would get a ...

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