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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How do you write fractional hydrates in words?

Apart from sequihydrate and hemihydrate (1.5 and 0.5 respectively), I can't find a way to write any other fractional hydrates. Wikipedia states: The notation "hydrated compound⋅nH2O", where ...
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2 votes
1 answer
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What is m.2m point group?

I'm using Bilbao Crystallographic Server to find 3D crystallographic point groups of the K points of anatase TiO2. Since the space group of anatse TiO2 is $I4_1/amd$, on this page, I found the point ...
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Drude model for semiconductors

I was wondering why we cannot use the classical model of conduction for semiconductors. We can express the concentration of free electrons and holes $n_{e} = n\cdot e^{-\frac{E}{kT}}$ where $n$ is the ...
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How Amorphous solids are converted to Crystalline?

I know about a process of Annealing where a crystalline solid is heated to its melting point and then cooled rapidly so as to form amorphous solid which has random crystallite in uts structure. But ...
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11 votes
2 answers
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How can brass still be made even though the crystal structures of zinc and copper are not the same?

Based on the Hume-Rothery rules, to dissolve an element into a metal, the crystal structures for both must be the same. But the structure for zinc is HCP, whereas copper has FCC structure. It does not ...
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How do other elements fit into a diamond's carbon lattice (e.g. nitrogen in yellow diamonds)

Traditional pure-carbon diamonds have a simple structure (tetrahedral, if I'm not mistaken). But common types of diamonds have other elements within them. For example, yellow diamond has nitrogen in ...
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What is the net gain of charge carriers in a semiconductor if an atom is removed?

In pure germanium, all Ge atoms are bonded with a tetrahedral geometry. It has a band gap and is a semiconductor. If we remove one Ge atom, what type(s) and how many charge carriers will be generated? ...
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why an interstitial defect increases density in covalent solids and do not increases in ionic solid?

The interstitial point defect increases the density of a solid. Frenkel defect is also a type of this defect but it do not increases the density. Also, the mass / volume concept of density tells us ...
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Two atoms exist in the same coordinate position in the lattice?

I am trying to simulate the properties of FeF3(H2O)3, so I download its crystal structure file from Crystallography Open Database, but it seems that in the lattice, ...
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In calculating the radius ratio in a tetrahedral site in an FCC lattice, why do we take tetrahedral void in the middle of the body diagonal line? [closed]

When calculating the ratio of cation / the ratio of anion in a Tetrahedral system in an FCC lattice, why do we take the void to be in the center instead of it being √3a/4 from the corner.
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Why does density decrease when pressure is increased on an NaCl type lattice?

I was told that the effect of pressure on an NaCl type structure would make the atoms come closer and therefore change the type to CsCl type making Z (no of atoms per unit cell) go down, hence density ...
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What is the paramagnetic susceptibility of sodium at around room temperature?

Proposed solution: This question comes from Tanner's manual Introduction to the Physics of Electrons in Solids, at the chapter dedicated to the application of the Fermi gas model. The Fermi energy is $...
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Restoring potential of atoms in a solid

Above $\pu{0 K}$ the atoms in a solid are vibrating. However, what kind of potential restores each atom in the starting position? Consider the crystal lattice of NaCl. The potential energy of a $\ce{...
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1 answer
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Balancing a chemical reaction with oxidation numbers

We have been teached how to balance chemical reactions with oxidation numbers in school, but somehow I can't understand it. This is the equation to balance $$\ce{Cu(s) + NO3−(aq) + H+(aq) -> Cu^2+(...
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Why Lambert's law does not hold for photoresistors?

Why don't photoresistors made of Si obey Lambert's cosine law? Is it related to the dark current of the photoresistor? I couldn't find any solution while searching the web.
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1 vote
1 answer
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Comprehensive list of metal alloys along with Moh's hardness scale

Material property lists, such as springermaterials.com, has lists of metal alloys and their properties. Is there a similar website that lists alloys along with their Mohs scale hardness? For ...
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2 votes
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Why do silver halide crystals in suspension, develop a surface charge

This is a question related to analog photography. Photographic films have a suspension of silver halide crystals in them, and these crystals have adsorptive properties which are used in this ...
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For a given packing (hcp, fcc, bcc), which ions occupy the corners and which occupy the faces or centers?

I recently came across the packing of atoms in unit cells. I wanted to know if there was a way to tell where the atoms in the unit cell are just by knowing the compound and its packing (hcp, fcc, etc.)...
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Is dehydration of cobalt(II) chloride hexahydrate dynamic equilibrium?

I know that the dehydration of cobalt(II) chloride hexahydrate is a reversible reaction, is it a dynamic equilibrium? $$ \begin{align} \ce{CoCl2·6H2O &<=> CoCl2·2H2O + 4 H2O}\tag{R1}\\ \ce{...
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Determine anion radius in FCC cell

The edge length of an FCC cell is $\pu{508 pm}$. If radius of cation is $\pu{110 pm}$, the radius of anion is? My approach: $$(2R_{\text{cation}}+2R_{\text{anion}})^2=2a^2$$ Which on simplification ...
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1 answer
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Adsorption on solids - homogeneous/heterogeneous surface definition

How could we define homogeneous and heterogeneous surfaces (rigorously)? It is among my exam questions (but I could not find any definition in my textbook or on the internet). I would say the ...
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3 votes
1 answer
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What is the maximum length of peptide which considered to be hard for synthesis by the current technology?

I am a molecular biologist and work with recombinant proteins. I am wondering what the cut point, in terms of length, is at which I should produce the peptide using heterologous expression rather than ...
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-1 votes
1 answer
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How many 4th nearest neighbours are there in an hcp lattice?

My teacher told us that there are 18 4th nearest neighbors in an hcp lattice, at a distance of √3a . I have only been able to identify 12. Can you help me find all the 4th nearest neighbors?
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Why do we have to use octahedral voids for formula making in solid state chemistry?

Allow me to take an example to explain myself. Q) What is the formula of a compound in which the element Y forms a ccp lattice and an atom of X occupy ${1\over3}$rd of tetrahedral voids? Now to find ...
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6 votes
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Correct Definition of Absolute Electrode Potential

I thought absolute electrode potential is Galvani potential difference at the interface. However, it is given by following equation in John Bockris - Modern Electrochemistry (Ref.1): $$ E^M \mathrm{(...
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2 votes
1 answer
140 views

Understanding packing in different dimensions

In one dimension, there is only one way of packing, that is keeping the balls next to each other. In two dimension, we can keep a line of spheres on top of another line directly or we can keep the ...
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1 vote
1 answer
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Radius ratio of octahedral interstitial site in BCC lithium

Problem Determine the minimum radius of an atom that will just fit into (a) the tetrahedral interstitial site in FCC nickel and (b) the octahedral interstitial site in BCC lithium. Solution (a) For ...
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Why is cuprous oxide a p-type semiconductor?

Wikipedia — Copper(I) oxide says $\ce{Cu2O}$ has semiconducting properties without any explanation. Nolan [1] talks about $\ce{Cu^+}$ vacancies making copper(I) oxide an extrinsic p-type semiconductor,...
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HCP and hexagonal primitive cell [duplicate]

There are 14 types of Bravais lattices one of them is hexagonal which is just present as primitive cell ie the basis are at its corners , now when I read about hexagonal closed packing I came to know ...
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7 votes
1 answer
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In solid-phase peptide synthesis, why are the formation of aspartimides a problem but not "glutamides"?

I'm studying solid-phase peptide synthesis (SPPS) at the moment, and a common problem is the formation of aspartimides, which disrupt the synthetic process. I understand how they form and why are they ...
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Why are there exactly 5 types of two-dimensional lattices, and what distinguishes them?

In the book Chemistry: The Central Science, they introduced the following 5 types of two-dimensional lattices: The book said that the blue square represents the unit cell, the black dots are lattice ...
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Bond formations in doping of semiconductors [duplicate]

I was reading about semiconductors and found out that semiconductors are doped with either 13th group or 15th group elements which are named p-type and n-type semiconductors, respectively. In n-type ...
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1 vote
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High symmetry points and x-coordinates

Is it possible to work out the x-coordinates related to high symmetry points? The software I'm using doesn't provide me with that, so I was wondering if there is a way to manually figure it out, as I ...
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3 votes
1 answer
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Cationic vacancies created when non-stoichiometric iron oxide is doped with silicon(IV) ions

Problem It is believed that non-stoichiometric compound $\ce{F_{0.93}O}$ forms by doping of $\ce{Fe^3+}$ ions in $\ce{FeO}$ crystal by replacement of $\ce{Fe^2+}$. Calculate the number of cationic ...
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6 votes
3 answers
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Why is sea salt coarse?

What makes sea salt coarser than other salt? I have tried checking online but no one seems to discuss this. It seems that the grain of sea salt is larger, but I don't understand since the salt is ...
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2 votes
0 answers
72 views

What makes up the conduction band?

Prologue/Rant about online classes We have been taught the electron sea model to explain metallic bonding and conduction of electricity by metals. Then out of the blue, the band theory was introduced, ...
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Unit cell of hcp structure

It is given in my book that the structure in figure-1 is the unit cell of hcp structure. So why then is the structure in figure-2 not the unit cell as we can repeat the structure in figure-2 to get ...
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2 votes
1 answer
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Why is the disordered CuAu structure more stable at high temperatures?

I know that the disordered CuAu structure is based around FCC whereas the ordered CuAu structure is tetragonal. Why would the FCC structure be more stable at high temperatures? For context, I was ...
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4 votes
1 answer
109 views

Getting an “index” of 7 for a set of powder diffraction data

I tried to index powder diffractogram from the following problem: A metal (of density $\pu{0.862 g cm^-3})$ gives the following powder X-ray diffraction data $(\lambda = \pu{1.5418 Å}).$ $$2\theta \...
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-3 votes
2 answers
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Coordination number of 3D close packing [closed]

Can anyone explain me that how the coordination number of corner sphere of this 3-D packing is 6 ? it should be 3
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How many types of 3D packing are possible?

In my book it's said that there are 3 types of unit cubic cell - primitive , face and body centered . But for 3d packing types they have only mentioned FCC and HCP . I know that these 2 concepts- ...
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2 votes
1 answer
158 views

On the exact definitions of Frenkel and Schottky defects

The wiki page on vacancy defects says; It is also known as a Schottky defect, although in ionic crystals the concepts are not identical. As far as I'm aware, they're the same. Furthermore, the wiki ...
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Pressure vs electric conductivity in solids

If we apply pressure to a solid, does it change its electric conductivity? I am asking this because in 2020 they announced a superconductor at room temperature but under a pressure of 3/4 of the ...
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0 votes
1 answer
171 views

Height of CCP Lattice

Are the height of the Cubic Close packing Lattice and the cubic Hexagonal Close Packing the same? My understanding says that these unit cells are formed by different arrangement of atoms, ABC for CCP ...
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4 votes
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Why is ruthenium dioxide a conductor while titanium dioxide is an insulator?

Ruthenium dioxide has the same crystal structure as rutile (titanium dioxide), and the metal atoms are in the same oxidation state. Yet ruthenium dioxide is a metal-like conductor (its resistivity is ...
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1 answer
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How is Gibbs free energy related to stability? [closed]

I have been learning thermodynamics for quite some time and I fail to relate Gibbs free energy and stability. For example, how do I compare stability of metal oxides using the following data? Also, do ...
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Interatomic spacing vs electric conductivity

I have a theory which may be wrong but I will write it down.If 2 elements at the same group (in solids)have the same crystal structure then the one with the biggest interatomic spacing has better ...
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2 votes
2 answers
114 views

Clarification of term symbol explanation of laser crystal doping from textbook

I am currently studying the textbook Diode Lasers and Photonic Integrated Circuits, second edition, by Coldren, Corzine, and Mashanovitch. Chapter 1.2 ENERGY LEVELS AND BANDS IN SOLIDS says the ...
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2 votes
2 answers
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Silicon–Boron Covalent Bond

This is a semiconductor-related question, but in order to understand the acceptor level energy state of boron in bilicon, I figured I'd ask here for hints. Boron is a p-type material when introduced ...
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0 votes
1 answer
225 views

Is the lattice point in ZnO crystal structure occupied by the molecule ZnO or the ion O^2-/Zn^2+?

I learnt that ZnO has a hexagonal crystal system. I was expecting that cations or anions would occupy the lattice points in hcp while voids would be occupied by anions or cations respectively. But ...
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