# Tagged Questions

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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### Calculating vacancies in crystal structure

I have this question on a practice exam. I'm not quite sure how to find the number of vacancies when replacing atoms. Question: The stable oxide for lithium is Li2O. How many oxygen vacancies in ...
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### Chemical structure of SiO2 vs CO2 [duplicate]

why does SiO2 form a crystal structure while CO2 forms a linear one? Would it be possible to make a CO2 crystal or SiO2 gas in a lab or is there something preventing that from happening. Thanks
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### Which elements exhibit allotropy?

I was just reading this article about allotropes which relates allotropy with some specific elements and also this wiki article. Also some other articles some of which relate allotropy with catenation ...
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### Calculating Transient Nucleation Rate

Let say, at each discrete time step, $t_i$, we can forecast of a transient nucleation rate, $I_{trans}$ by following formulation: I_{trans}(t) = I_{ss}. \sqrt{(\frac{A\tau}{t})} .e^{-\frac{B\tau}{t}...
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### Crystallography - physical reason for ideal lattice approx

Why can we approximate a lattice as being infinite when we describe it as an ideal crystal? Is there any physical reason or is it just because the number of ions (/atoms) is so huge that we can treat ...
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### In powder x rd, if the crystals are randomly oriented ,why then do we get Debye rings and not random patterns?

In powder x-ray diffraction ,as I have learnt the sample is multi-crystalline.So if x-ray is diffracted through these randomly oriented crystal grains, aren't we supposed to get a random pattern?
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### Is the plane close packed?

Is the (200) plane of fcc crystal structure(the plane parallel to the face of unit cell and passing through the body centre of it) a close packed plane? A close packed palne is a plane where the ...
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### Is (high) pressure required to form (quartz) crystals?

I've been reading a lot of sources about the hydrothermal synthesis of quartz using autoclaves. I want to try doing this myself, but before I can I need to know the minimum pressure required. If you ...
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### What hinders Monoclinic crystal system from having face centered variation and body centred variation?

Base centered monoclinic cubic cells exists.I think that we can just place some lattice points at the center of other faces to get a Face-Centered structure. But, Two monoclinic Bravais lattices ...
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### Alternative to Hanging Drop Crystallization

Forgive my ignorance if I am way off, but I was having a look at the crystallization of a number of different substances (e.g. proteins) through the hanging drop vapour diffusion method. The examples ...
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### Understanding three-dimensional structure of common salt

I started reading through The Feynman Lectures and came across this diagram. What do the numbers next to the nodes in the diagram represent? It's not explained in the text. All that is mentioned is: "...
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### Copper density modification

Can you increase the density of a material surface (metal) by surface treatment? For example commercial copper. If we take the ordinary OF copper (99.95%), I would expect not to have the tabulated 8....
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### How does the colouration of alum crystals work?

I see the experiment of making potassium alum crystals in most places showing basic science experiments and some of them will include adding in food colouring to the solution in order to colour the ...
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### Edge length unit cells ionic crystals

In ionic crystals there are mainly 3 types of structures: Face-centered cubic and octahedral interstices; face-centered cubic with tetrahedral interstices; and body-centered cubic. My question is how ...
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### Is it feasible to make dendritic crystals at home?

I've become interested in the forms of dendritic metal crystals from an aesthetic perspective, and I'm interested in whether it is feasible (from a cost, safety, resources) perspective to create metal ...
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