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Questions tagged [solid-state-chemistry]

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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0answers
104 views

NiO and ZnO electrical conductivity with oxygen pressure

NiO is a Mott-Hubbard insulator and increasing oxygen concentration leads to anion excess and oxidation of Nickel so electron hopping is more favourable so electron repulsion is reduced and it becomes ...
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1answer
812 views

Why is potassium monoxide (K2O) coloured?

Potassium monoxide is rarely formed and is a pale yellow solid. I don't understand how is this compound coloured because in oxide anion electron cannot excite in the next orbital due to huge energy ...
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2answers
207 views

What makes certain zeolites better at ion exchange?

I would have thought that the bigger the pores in the zeolite, the more ions it can contain, and therefore the better the use of the zeolite for ion exchange. However, zeolite A has small pores but ...
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20 views

Is glass amorphous solid or supercooled liquid? [duplicate]

I've read that glass is a supercooled liquid. But lately I've came to know in a science info post that glass is amorphous solid. How? Please someone explain me.
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2answers
2k views

Melting Point of Amorphous Solids [closed]

My textbook says that amorphous solids do not melt at a fixed temperature,but at a range of temperature. It depends on the way the atoms/molecules are present in a given piece of solid. Since the ...
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2answers
45k views

How are the number of tetrahedral voids twice the number of octahedral voids in a CCP structure?

How are the number of tetrahedral voids twice the number of octahedral voids in a CCP structure? Is there some kind of mathematical proof for it? Is there some way I can understand this intuitively? ...
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0answers
1k views

Density of Interstitial compounds

I have read in my textbook (not very reliable) that density of interstitial compounds is lesser than parent compound. But how can this be true? We add atoms to the lattice voids, so density should ...
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77 views

Substituting Ulexite

I'm working on ceramic glaze chemistry. One ingredient I don't have, but want to substitute is ulexite: $$\ce{NaCaB5O6(OH)6.5H2O}$$ I have borax, calcium borate, and calcium silicate: $$\ce{NaB4O7 ...
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17 views

Surface-dependency of kinetic in speed law?

we can comprehend the quantitative dependency of the kinetic of a chemical reaction through the speed law: $v(t) = k \cdot c(...)^k \cdot c(...)^n$ Here I used the concentration $c$ for that take ...
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3answers
411 views

What does β stand for in β-potassium zirconate?

What do the Greek letters (α, β, γ...) convey when they are prefixed to a crystalline substance? For example: β-potassium zirconate
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1answer
72 views

Is there a substance that is hard (ideally abrasive) in solid form but would dissolve in water?

doing some research for a dishwasher / dish cleaning product and interested in any compounds that could be fashioned into a brush or other abrasive form and then dissolve and wash away with the water ...
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1answer
187 views

Band gap of Transition Metal Dichalcogenides

What phenomena is responsible for the shift of the nature of the band gap of transition metal dichalcogenides from being indirect band gaps to direct band gap material once it is slimmed down from ...
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1answer
916 views

Reaction speed with solids

It seems that reaction rate is defined as change of concentration over time and the speed doesn’t change if you add more solid. But imagine we have a cube (1 kg) of $\ce{CaCO3}$ that yields 1 mole $\...
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1answer
767 views

Is Changing between Allotropic forms a Physical or Chemical Process?

When a substance changes its alloptropic form, is this considered a physical change or a chemical change? Right now, I am thinking that it would depend on what the change was. For example, if ...
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474 views

Distance between two atoms that lie along a body diagonal

It is given that two atoms lie along the body diagonal of a unit cell (crystalline solid). The length of such cubic cell is $a=\mathrm{0.336\,nm}$. My book says that we should take the coordinates of ...
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1answer
5k views

Coordination numbers and radius ratio

According to the image above (source), for a radius-ratio between 0.732 and 1, the coordination number is 8. However, for a radius-ratio of 1, the coordination is 12. This is the same for the boundary ...
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1answer
300 views

Which it is the oxidation state of indium and phosphorus? [closed]

I would like to know what the oxidation state of indium and phosphorus in a structure type rock salt. It could be +1 and -1? Yes or not? and why? Thanks
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1answer
3k views

What is crystallographic equivalence?

I’ve learnt that in crystallography, there are many crystallographic directions that are “equivalent.” For example, in a cubic crystal system, the [011] and [110] and [101] directions are “...
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1answer
739 views

Calculating the ionic polarizability from the Clausius-Mossoti relation

The concentration of atoms in a crystal is $N_d = \pu{2.24e28 m-3}$, and the relative dielectric constant is $\varepsilon_{r} = 5.62$. The crystal has a refractive index of $n = 1.5$. Using the ...
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2answers
664 views

Cubic crystals anisotropy

My textbook states "Cubic crystals contain four three-fold axes, converting the ellipsoid to a sphere." What indeed is the ellipsoid and sphere in the lattice? I know the meaning of three fold ...
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1answer
415 views

Primitive cells and their variations

Is there any intuitive way(without involving higher maths) to explain possible variations in seven primitive types of (unit)cells? I would like explanation in context of why end centred is possible ...
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0answers
251 views

Interstitial Sites in unit cell

I wanted to calculate how many interstitial sites (tetrahedral and octahedral) are present in a simple unit cell and their location and radius. I am guessing they are at the center of unit cell and at ...
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0answers
222 views

Solid State - Radius Ratio rules

Why lithium salts crystallize in octahedral lattice , although radius ratio values are much below than expected ratio?
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1answer
136 views

Why does the barium ion in barium titanate move in its tetragonal crystal structure?

Barium titanate is known in the materials science world to be a great dielectric. This is known to be because the $\ce{Ba^2+}$ ion sits off center in the middle of the tetragonal crystal structure. ...
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1answer
49 views

Cutting a Solid with a sharp edged tool

The third point of difference suggests that amorphous solids can't be cut into two parts of regular surfaces But glass being an amorphous solid is cut into regular pieces often. What am I getting ...
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1answer
126 views

Determine the quantitative composition of a solid sample containing Co, Mn, Al, C, and O

I have a solid sample that contains Co, Mn, Al, C, and O. The sample mass is ~200 mg. I need to determine what the composition of this sample is. I've looked at atomic adsorption spectroscopy, but ...
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1answer
63 views

Defects of Crystals

So while studying defects, I found that: Interstitial defect is when constituent particle is present in the interstitial site. My question is where this constituent particle is coming from? As it ...
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1k views

Voids vs Interstitial Site?

I am studying solids states. So we studied different lattices of Ionic solids by introducting smaller Cations into VOIDS. Next topic is of defects. SO it is written Frankel defect arises when a ...
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0answers
83 views

19F MAS NMR chemical shift tensor and the crystal structure

$\ce{^{19}F}$ MAS NMR is measured on fluorine-doped $\ce{TiO2}$. $\ce{F}$ is to substitute $\ce{O}$ and the crystal structure is anatase, which has a tetragonal crystal system with a space group $\ce{...
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587 views

Why are certain reflections forbidden in body centered cubic and face centered cubic structures?

I know that for body centered cubic structures the allowed reflections only happen if h+k+l is even and reflections are forbidden is h+k+l is odd, and for basic face centered cubic structures (...
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1answer
865 views

Fraction of cube Volume empty [closed]

The unit cell in a body centered cubic lattice is given. Each sphere has a radius r and the cube has a side a. What fraction of the total cube volume is empty?
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50 views

Band alignment of heterojunctions

I have seen several band bending diagrams in journals and the web. However, I am not sure as to how they align them. Some diagram appear to align the vacuum level and some align them by Fermi Level. I ...
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1answer
851 views

Zinc oxide reduction in ethanol

I'm trying to prepare a ZnO thin film deposited on a glass substrate. The precursor solution prepared by sol gel process through dissolving 1 M zinc acetate dihydrate $\ce{Zn(CH_3COO)_2.2H_2O}$ in ...
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1answer
12k views

Why are X-rays used in crystallography?

Can any other wavelength of electromagnetic radiation be used? Why can't gamma radiation be used?
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1answer
250 views

Why can't two Silicon tetraoxide tetrahedrons share an edge or a face?

Our teacher told us about structural types of silicate minerals (neosilicate, sorosilicate, cyclosilicates ...) saying that those tetrahedrons can only share one corner (oxygen), but he didn't give us ...
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1answer
802 views

Materials with solid volume greater than liquid volume

Water has a solid volume greater than its liquid volume. This question is in two parts. 1) Are there other materials that have solid volumes greater than liquid volumes? 2) What about the structure ...
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2answers
1k views

Colour due to F-centre is same as that produced in a flame test, why?

I have noticed that the colours that the F-centres impart in Alkali metal halides are the same that the corresponding alkali metals impart to their flames. $\ce{NaCl}$ when heated in an atmosphere of ...
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0answers
265 views

What are the physical properties of exotic ice?

This chart shows the phases of water that form at various combinations of pressures and temperatures. It has multiple exotic forms of ice (labeled II through XV) listed. What are the physical ...
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1answer
9k views

How to calculate Madelung's constant for NaCl?

Madelung's constant for $\ce{NaCl}$ is $1.748$. What I tried to so is sum up all the individual interactions into $1$ component where the $X$s are the nucleus and the electron if it was a $2$ atom ...
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1answer
107 views

How can the bulky octadecyltriethoxysilane molecule promote single-crystal growth?

Octadecyltriethoxysilane is very bulky (source), yet it was used to promote single crystal growth (source). How can such a bulky molecule induce crystal growth? (For example epitaxial growth happens ...
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1answer
130 views

What is the structure of powdered sulfur?

Quoting this paper: A variety of allotropic states of elementary sulfur have been identified. Solid crystalline sulfur exists either as rings of 6-12 sulfur atoms (cyclohexasulfur, $\ce{S6}$, ...
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0answers
81 views

How dangerous are non-soluble trivalent thallium compounds?

I am PhD student in solid state physics. I have been working with a fine powder of a transition metal oxide containing trivalent thallium. The oxide is not soluble in water. In my university, ...
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2answers
461 views

Oxidation state of metal ion in unit cell

If a cubic unit cell for a metal nitride has nitride ions at all face and corner positions, and metal ions at all edge positions, what is the oxidation state for the metal ion in the nitride? I ...
2
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0answers
31 views

Reference request for properties of amorphous titanium carbide (a-TiC)

I assume through some side reaction I'm getting $\ce{TiC}$ in my $\ce{TiO2}$ samples after calcination and I need some basic information about the properties of amorphous $\ce{TiC}$. Is it ...
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0answers
58 views

What is the difference between phase of matter and state of matter? [duplicate]

I am still confused on the differences between the phase of matter and state of matter
3
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1answer
368 views

Why some compounds form different crystal structure at different temperature?

Lets take an example :- Sodium superoxide has three different crystal structure, the marcasite structure at nearby 81 K, the pyrite structure between 196 K and 223 K and calcium carbide ...
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1answer
478 views

Relationship between coordination numbers and stoichiometry

In fluorite ($\ce{CaF2}$), the coordination number of $\ce{Ca}$ is $8$, and that of $\ce{F}$ is $4$. Is there any logic behind the ratio of coordination numbers being the same as the stoichiometry of ...
3
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1answer
5k views

What is the lattice structure of manganese?

A transition element is defined as the one which has incompletely filled d orbital in its ground state or in any one of its oxidation state. Zinc , cadmium and mercury are not typical transition ...
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1answer
123 views

Refractive properties of materials?

I've just read this article about meta-materials with 0-refractive index, which potentially may "permit" light with super-luminous rate /under rate is meant the propagation of light's phase, which ...
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1answer
329 views

How to eliminate electrostatic charges from titanium dioxide powder

I have synthesized $\ce{TiO2}$ nanoparticles via sol-gel method and I need to calcine it at elevated temperatures for the crystal phases formation. The powder is very highly charged and not only ...