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1answer
34 views

Salts of hydronium ion

Are there any solids with hydronium ion in its crystal structure? If so, what are they? If not, why not? I understand there are hydroxide-containing solids and gels such as aluminium hydroxide but ...
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0answers
42 views

How does the crystal know where to stop stacking the unit cells?

I tried to make different crystals in the cubic system by stacking cubes in a 3d software. However I need to tell the software where to skip rows or stop stacking the unit cells in a specific ...
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1answer
27 views

Octahedral Voids

The total number of octahedral void(s) per atom present in a cubic closed pack structure is (a) 1 (b) 2 (c) 3 (d) 4 PS- I answered it (d) 4 but a key on internet says it is (a) 1. Please clarify ...
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1answer
61 views

About the nomenclature: manganate or manganite?

I am a bit confused about the correct name of $\mathrm{LaMnO}_3$. Is it lanthanium manganate or lanthanum manganite? I was assuming that since $\mathrm{SrTiO}_3$ is called strontium titanate, ...
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1answer
34 views

Why there exist no void with co-ordination number 5

Here oh = octahedral td = tetrahedral CN = co-ordination number My problem is that, that why it is not possible to have a void with CN ...
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1answer
59 views

What is the minimum distance of Rubidium and Iod ions in a centered cube?

I have a problem to visualize the following assignment: What is the minimum distance between $\ce{Rb^+}$ and $\ce{I^-}$ ions if radius of $\ce{Rb^+}$ is ${1.49\cdot10^{-10}}~\mathrm{m}$ and radius ...
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2answers
212 views

Boyle's Law of pressure and volume

Boyle's Law states that: Pressure is inversely propotional to Volume. But if we take an example of a balloon. As we fill air in it it's pressure increases but it's volume also increases. Can anyone ...
5
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1answer
152 views

Is pyrite (FeS2) an ionic or a covalent compound?

I have searched all over the web and found a lot of diverse explanations, but none of them are concluding exactly whether $\ce{FeS2}$ (solid - pyrite) is a covalent or an ionic compound. From ...
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1answer
334 views

What is the Melting point of diamond?

the melting point of diamond, I Googled it out but textbooks and the online reference differ there more than two answers,please help.
2
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1answer
75 views

What is the (conceptual) difference between binding energy and adsorption energy?

I know the equations, but I have some difficulty getting the difference between the two concepts of binding energy and adsorption energy.
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2answers
104 views

Why do amorphous substances have different values of physical properties in different directions?

Today my teacher taught about amorphous and crystalline substances. Crystalline substances are said to have different values for physical properties (like speed of light, electrical resistance, etc) ...
3
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0answers
50 views

How are non-Stoichiometric compounds determined?

For solids where the compound contains defects, the stoichiometric equation deviates from the "pure" one. How are these compounds determined? I am looking in my chemistry book but I do not see ...
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1answer
2k views

How to determine whether a compound is gas or liquid or solid?

My book says, methyl chloride, methyl bromide, ethyl chloride and some cholorofluromethanes are gases at room temperature, whereas higher members are liquids or solids. Why? With this question, I ...
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2answers
815 views

Is it possible to melt diamonds into a liquid?

Is it possible to melt diamonds into a liquid? I mean if you heat diamond at open air it will start to burn around 700 degree celsius, reacting with oxygen to produce carbon dioxide gas. In the ...
2
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1answer
42 views

Why polymorphs form?

We always hear about the different arrangements of molecules that lead to the formation of polymorphs, my question here is why would a polymorph form in the first place? The material was given enough ...
3
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1answer
71 views

Solvated solids

I have a very basic question concerning solvation. If a solid (solute) was dissolved in a liquid (solvent), is the solute still in the solid state? or does it convert into another state of matter when ...
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0answers
557 views

Stoichiometric defects in ionic crystal?

The stoichiometric defects (Schottky and Frenkel defects) in ionic crystals are formed due to irregularities in ionic arrangement all the while maintaining the stoichiometry and electric neutrality. ...
4
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1answer
3k views

What is the principle of diffuse reflectance spectroscopy behind band gap measurement?

As the title suggest can you explain how DRS can be used for finding band gap of a material. Below is an DRS output result: From the figure we can see that at about 465 nm the reflectance drops ...
3
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1answer
95 views

Thermodynamics behind Deliquescence?

The phenomenon of deliquescence wherein a water soluble substance absorbs water from atmosphere and dissolve in it forming a saturated solution, has thermodynamic roots. I have read the fact that the ...
2
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1answer
61 views

Structure of N₅P₃?

What is the structure of the molecule N₅P₃? N₅P₃ is not documented online so could anyone please say the structure of the molecule: How many ligands does each Phosphorous atom have? How many ...
5
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2answers
121 views

Removing titanium from tantalum crucible

I'm trying to remove titanium filling from a tantalum crucible for a high-temperature effusion cell. I've managed to get a majority of the material out with tweezers, but some remains and is ...
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2answers
896 views

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 ...
0
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1answer
22 views

What is the difference between a chemical state and just a combination?

I don't think a combination also can be called a "state" i.e. that the chemical state of vapour or solid would be just a combination. When I read Wikipedia about "chemical state" it refers to just a ...
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1answer
151 views

Are chiral quasicrystals possible?

Quasicrystals are materials that have long-range atomic order but lack the translational symmetry of conventional crystals. All quasicrystalline tilings and packings I have read about thus far, whilst ...
2
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1answer
78 views

Ionic Radius of Iodine in High Temperature Form

The ionic radius of iodine in the high temperature form can be determined once the unit cell is known, but how can I calculate the radius of $\ce{I}$ given that the cubic lattice parameter is 6.10 Å. ...
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vote
1answer
64 views

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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votes
2answers
223 views

Why does an ideal capacitor give rise to a rectangular cyclic voltammogram (CV)?

This question is sort of a sequel to my previous question about cyclic voltammetry (CV). One of the responses made reference to the fact that an ideal capacitor gives rise to a rectangular cyclic ...
2
votes
1answer
4k views

How to find the band gap for a compound?

I have processed a si/polymer hybrid using a silane coupling agent which I need to determine the energy gap / band gap. Would you please let me know the procedure to go about determining the band ...
4
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1answer
57 views

Has QTPIE ever been applied to 1D metals such as polyacetylene?

QTPIE is a fluctuating charge model that substantially improves modeling of polarization and charge transfer. I was curious whether it has ever been applied to 1D metals such as polyacetylene to ...
6
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1answer
244 views

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 ...
8
votes
1answer
500 views

How are turbostratic graphite phases formed?

Turbostratic graphite is graphite in which there is quenched rotational disalignment between adjacent graphene sheets, i.e. one sheet is rotated with respect to its neighbor. I suppose this could be ...
8
votes
1answer
81 views

Is there a theory behind selecting elements that may be successful in potential superconductors?

Looking at something like $\cf{ YBa{_2}Cu{_3}O{_7}}$ which was one of the first cuprate superconductors to be discovered, I'm always curious how the selection of these substances as likely ...
9
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4answers
746 views

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 ...