Study of chemical species that are in solid phase, either in cases of their properties, or about ways of synthesizing them.

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Stability of radium oxide

Why is radium oxide yet to be isolated when a wide range of other radium (II) compounds are known ?
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Why is the electrical conductivity of Cu(I) better than that of magnesium?

My professor said it is because each atom has a different electron and atomic nucleus structure, so bond distance changes. But in some cases orbitals overlap which causes the band gap to disappear. My ...
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57 views

What is the world's finest powder substance?

What is the world's finest powder substance that has the smallest granules but remains solid?
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1answer
24 views

Are molecular optimisations in Gaussian really the optimisations of molecules in vacuum?

I knew that Gaussian assumes the molecule is alone in vacuum, that is, the molecule doesn't interact with anything, when optimising the molecule. But I've found that Gaussian's optimisation(at HF or ...
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Interstitial sites: edge and face sharing?

In close packed structures there is one octahedral hole per close packed atom. In a HCP unit cell these octahedra form a chain of face sharing polyhedra. Is this this universal in close packing or ...
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297 views

How does chromium help stainless steel prevent rusting?

Various sources (such as this one) say that stainless steel is stainless because a passivation layer of an oxide is formed, but I haven't found details on why chromium helps create this passivation ...
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27 views

Why so differance in alkali halide's crystal forms?

I always wonder that though Both $\ce{NaCl}$ and $\ce{CsCl}$ are alkali halides, why they adopt different crystal forms, FCC and BCC respectively? and I have a doubt about $\ce{CsCl}$ structure that ...
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23 views

Is hydrolytic polymerisation the mechanism by which the precipitate forms from the neutral complex?

From basic coordination chemistry and acid-base equilibria we understand that a metal hexa-aqua ion can be deprotonated until it's positive charge is balanced by the negative charge of the hydroxides ...
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58 views

Distance between successive tetrahedral voids in FCC

What is the distance between successive tetrahedral voids in a FCC Crystal structure? The distance between a face centered atom and a tetrahedral void is $\sqrt{\frac{3a}{4}}$ if the cube's edge ...
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40 views

Is there a way to turn alcohol into a solid gel?

I'm wondering if there is a way to turn alcohol or another bacteria killing substance into a solid gel form, sort of like the gel you can use to clean a keyboard. Source: Aliexpress.com Computer ...
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1answer
32 views

Coloration of substances because of F-Centers

In case of metal deficient defects in the crystal lattice of a metal, the positive voids are filled by electrons. How does this result in the coloration of a substance? Does this condition arise ...
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1answer
35 views

Unit cell of CdCl2

I understand that $\ce{CdCl2}$ has a rhombohedral unit cell as shown in this book. However I often find it being referred to as a "CCP analogue" of $\ce{CdI2}$. Presumably it is the chlorides which ...
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152 views

Are all lattices Bravais lattices?

Can all lattices be described as one of the fourteen Bravais lattices? Is the hexagonal close packed structure also one of the fourteen Bravais lattices?
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30 views

Amorphous to crystalline: Opposite trend?

Well my book says that on heating- amorphous solids crystalline at some temperature. As far as I know , amorphous solids have a very disordered structure compared to crystalline solids and on further ...
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67 views

Formula of a cubic lattice

Question: In a cubic lattice of XYZ, X atoms are present at all corners except one corner which is occupied by Y atoms. Z atoms are present at face centres. What is the formula of compound? ...
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54 views

How to predict the ³¹P NMR spectra?

What can I predict about the $\ce{^{31}P}$ spectra of $\ce{TiP2O7}$? To get the required information about the crystal structure of the compound, here is a screenshot from the ICSD website: Since ...
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2answers
57 views

What allows all 3 states of H₂O to be present at the same time?

How is it possible for there to be a glacier floating on water but under clouds? Depending on the temperature, shouldn't there only be one state of water?
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112 views

What is the actual reason behind PCl₅ existing as an ionic solid?

Why does $\ce{PCl_5}$ exists in the solid state as $\ce{[PCl_6]^{-}[PCl_4]^{+}}$? What is the problem with it that it doesn't exist in its original form in solid state? Like why isn't it just ...
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42 views

In ionic solids such as NaCl, do the cations fill interstital holes in the cation's cubic close pack structure? [duplicate]

Are binary ionic solids like $\ce{NaCl}$ comprised of a cubic close packed structure of the anions with the cations filling interstital holes or do the cations and the anions contribute to the cubic ...
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48 views

Cohesive forces in solid solutions

I have searched through printed books and the Internet, but I cannot find a definitive answer on an issue that fascinates me: what forces keep the various compounds belonging to a solid solution ...
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So of the different characteristics of a XRD plot, wich is most appropiate to identify and suggested one phase among others?

This is the XRD Powder plot of a sample prepared with {La, Ti, K and O}. Thanks a lot for your suggestions. So of the different characteristics of a XRD plot, which is most appropriate and suggested ...
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80 views

Why does a liquids height in a Barometer depend linearly on pressure?

Here is a derivation I found relating the pressure P, gravity g, height h, and density $\rho$, of a liquid in a barometer $$ P=\frac{mg}{A}\\ V=Ah \\ P = \frac{mgh}{V}\\ \rho=\frac{m}{V}\\ P = \rho g ...
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1answer
95 views

Rock Salt structure

Source BY looking at this structure of rock salt (NaCl) we can say that the chloride ions and the sodium ions have the same environment that is the nearby atoms position relative to that ion except ...
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Why do molecular orbitals in solids merge to bands?

Why do molecular orbitals in solids merge to bands? For example: In silicon every atom is sp3 hybridised, but when I merge two of these orbitals then it yields a bonding and an antibonding MO. When a ...
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Why are there no cheap diamond equivalents?

We recently learned in school that diamonds sparkle as the are very optically dense, meaning that it takes longer for light to pass through them, thus meaning that the light totally internally ...
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1answer
141 views

Coordination numbers of ionic and intermetallic compunds

If $\ce{NaCl}$ crystallizes in an fcc lattice, its coordination number should be 12. Then why do we say that $\ce{NaCl}$ has a coordination number of 6? Also, if $\ce{CsCl}$ crystallizes in a simple ...
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74 views

Cocrystals vs Eutectic mixtures

I was reading around about the different solid states of materials and I got to a point where I have reached the multi-component solids. I was not able to find a major difference between the cocrystal ...
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What is the carbon footprint of a diamond?

I think it would be interesting and illuminating to calculate the carbon footprint (per carat) of diamond. The answer would undoubtedly be different for artificial (industrial grade) diamonds vs. ...
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1answer
83 views

Carburizing Calculation

The problem is stated as follows: The surface of a steel gear made of 1022 steel (0.22 wt% C) is to be gas-carburized at $927$ °C. Calculate the time necessary to increase the carbon content to 0.30 ...
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1answer
94 views

Fick's Second Law of Diffusion

In the book "Foundations of Materials Science and Engineering" (Smith and Hashemi) the following is written: For cases of non-steady state diffusion in which diffusivity is independent of time, ...
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1answer
209 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 ...
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140 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?
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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.
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1answer
30 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 ...
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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 ...
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93 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 = ...
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77 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 ...
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198 views

What are Lattice Points

What are lattice points exactly? And Also How many Lattice Points are there in each of the Unit Cells?
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779 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 ...
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1answer
91 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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1answer
84 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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35 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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164 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
54 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
72 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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604 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 ...
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1answer
653 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
5k 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.
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230 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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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) ...