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2
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1answer
125 views

A semi-transparent material that is a solid

I am trying to find something I can get the ingredients for and make that starts out a liquid and sets into a solid. My end goal is to create a simple 8bit art figure so I want to pour it into a mold ...
2
votes
2answers
50 views

Why do different impurities create different colors in diamonds?

Traces of nitrogen make diamonds yellow while traces of boron make them blue. What accounts for the differences in color for a given element?
2
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0answers
22 views

Is there a compound where one element has a CCP structure with all voids occupied by others?

My Google-fu hasn't got me anywhere. All results have been quite fuzzy about it, nothing explicit.
0
votes
1answer
21 views

How do scientists check which kind of unit cell is present in a crystal?

There are many types of unit cells like: Tetragonal Monoclinic Orthorhombic Rhombohedral Hexagonal Triclinic Cubic But how do scientists identify the type when ...
5
votes
2answers
46 views

How do people check the type of defect in a crystal?

There are many types of defects like Vacancy Interstitial Schottky Frenkel Non-Stoichiometric Alien Impurities But given a sample, how do scientists know which kind of defect is present in it ...
0
votes
1answer
31 views

What is the length of a unit cell of CuCl assuming that it is fcc?

The density of CuCl is given - x gm/cmm The crystal structure is assumed to be fcc. My teacher is claiming the we can apply the formula $$\rho=\frac{Z * M}{a^3 * N_0}$$ And he took M = 35.5+63.5gm = ...
1
vote
1answer
42 views

Structure of diamond

"diamond structure. Every carbon atom is bonded to four other carbon atoms forming a three-dimensional lattice of chair conformations." SENTENCE FROM A BOOK What does this mean? Where I am struck ...
0
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2answers
24 views

What are Lattice Points

What are lattice points exactly? And Also How many Lattice Points are there in each of the Unit Cells?
5
votes
1answer
60 views

What causes photovoltaic (solar) cells to degrade?

Photovoltaic panels can have 20 or 25 year underwritten warranties with a guaranteed remaining efficiency of 80 % of the new panel. That means, that photovoltaic panels seem to degrade somehow. Why ...
1
vote
1answer
43 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 ...
6
votes
1answer
68 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 ...
0
votes
1answer
31 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 ...
1
vote
1answer
78 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, ...
2
votes
1answer
37 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 ...
1
vote
1answer
63 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 ...
1
vote
2answers
262 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
votes
1answer
198 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 ...
1
vote
1answer
782 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
votes
1answer
105 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.
1
vote
2answers
116 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
votes
0answers
59 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 ...
0
votes
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 ...
5
votes
2answers
1k 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
votes
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
votes
1answer
73 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 ...
10
votes
1answer
687 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
votes
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
votes
1answer
108 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 ...
3
votes
1answer
65 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
votes
2answers
124 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 ...
5
votes
2answers
1k 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
votes
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 ...
10
votes
1answer
159 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
votes
1answer
82 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. ...
1
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 ...
7
votes
2answers
229 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
votes
1answer
60 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
votes
1answer
254 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
525 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
83 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
votes
4answers
814 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 ...