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.
281
questions
2
votes
2answers
88 views
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 ...
0
votes
1answer
49 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 ...
0
votes
1answer
57 views
What is the form of the Hamiltonian for solids?
For atoms, and even molecules, I can understand how the Hamiltonian would be constructed, but what of solids (as in, for electronic structure calculations)? Thank you for any help.
0
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1answer
41 views
Interplanar distance given Miller indice of the planes
Say we've a cubic crystal of unity edge length.
A set of planes in such a crystal is specified by their miller indice as $(3 2 0)$. One of these planes then has intercepts on the axes as $(2 ,3 ,\...
1
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0answers
18 views
How to calculate planar density of a face /plane of crystal with cation and anions?
Planar density is given by numer of atoms in plane /plane area .
Suppose I want to calculate
planar density of 100, 101 and 111 planes of Nacl. Radius of Na+ and Cl- ions is 0.086 nm and 0.126 nm.Na+ ...
0
votes
0answers
22 views
Where are the tetrahedral voids and octahedral voids located in an FCC? [duplicate]
A crystal is made up of atoms X, Y, and Z. Atoms X are in FCC packing, Y occupy all octahedral voids and Z occupies all the tetrahedral voids. If all the atoms along two body diagonal are removed, ...
-3
votes
1answer
78 views
Ice geometrical shapes [duplicate]
https://en.wikipedia.org/wiki/Ice
https://www.google.com/search?q=ice&prmd=inmv&sxsrf=ALeKk028fJvrUcWLWu8EV-KsRGuiw0iWWw:1596098668929&source=lnms&tbm=isch&sa=X&ved=...
1
vote
3answers
139 views
Why water cools from outside to inside?
It is a well-known fact that
Water kept in a container, on cooling, results in freezing with initially at the circumference of surface
(1D), then on the surface (2D) and then throughout the volume (...
0
votes
0answers
29 views
“e and a” as combinations of pi bonds
I am trying to get a better intuition on solid-state physics but I am a chemist by degree. I came across this article that attempts to bridge the gap between solid-state physics and molecular ...
5
votes
0answers
53 views
How is the Born-Lande equation modified when the structure is not NaCl?
Often the Born-Lande equation is quoted (alongwith the calculation of the Madelung constant and Born exponent) with reference to rock-salt structure. But what if we take some other crystal, like ...
0
votes
1answer
24 views
Doping of a solid with impurities [closed]
This question is a continuation of the previous question of mine:press me if you wish
And my question is how can I dope a solid with impurities and if the process can be understood with basic ...
0
votes
2answers
109 views
How to identify if a material is perovskite or not?
This is more of a materials science question, but I believe many of you have referred NIST Inorganic Crystal Structure Database (ICSD) database.
I am collecting a database of perovskite materials and ...
-1
votes
1answer
105 views
Are HCP and Primitive Hexagonal Unit Cell the same thing? [closed]
In HCP, the [2D] Hexagonal packed layers are arranged in ABAB form. The same happens in Primitive Hexagonal Unit Cell. So does that mean they are the same? If not what differentiates one from the ...
1
vote
2answers
172 views
Why rutile structure have primitive unit cell instead of body centered?
In the literature (Wikipedia), I read that $\ce{MgH2}$ have a structure of rutile. Then, I looked at its space group which is $P4_2/mnm$. From this notation, I understood that it possesses a (...
0
votes
0answers
41 views
Do all metals expand on heating? [duplicate]
This question came up when I was reading about substances with negative thermal expansion. The article by Takenaka [1] gives a good list of materials displaying negative thermal expansion. I noticed ...
0
votes
0answers
48 views
How can fluorite structure exist?
From the information from Google the radius of $\ce{Ca^2+}$ cation is $100 \,\pu{pm}$ and of $\ce{F-}$ anion is $132\, \pu{pm}$, so essentially $\ce{F-}$ ion should form the Bravais lattice (FCC/CCP) ...
0
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0answers
48 views
Reason behind more prioritising of normal spinels
According to my textbook:
In normal spinels $\ce{A^{II}}$ should have occupied octahedral voids, but this factor is outweighed by greater lattice energy or smaller cation $\ce{B^{III}}$.
Later,
...
-3
votes
2answers
170 views
Change in the number of ions due to exchanging ions [closed]
If the position of Na+ and Cl- are interchanged in NaCl having FCC arrangement of Cl- ions then what change we can observe in the unit cell of NaCl.
I am confused as how the contribution will change ...
-1
votes
1answer
1k views
Calculate third and fourth nearest neighbours in fcc packing [closed]
My textbook has given data for third and fourth nearest neighbours to be 6 and 8 with distances a and √(3/2)a.
I have been able to calculate for the first and second nearest neighbour but it has ...
1
vote
2answers
44 views
Effect of pressure on transition temperature
I was wondering if someone can explain why the answer to the following question is volume instead of the others.
If pressure has no effect on the transition temperature between two
crystalline forms ...
2
votes
1answer
458 views
Is the number of tetrahedral voids always equal to double the number of octahedral voids in any crystal?
I came accross the question whether the number of tetrahedal voids is always equal to twice the number of octahedral voids (in the case where both the voids are present). The key was given as the ...
0
votes
0answers
19 views
Is the alloy of Fe, Si substitution alloy or interstitial alloy?
When atoms of the solute in a solid solution occupy positions
normally occupied by a solvent atom, we have a substitutional alloy. When the sol-
ute atoms occupy interstitial positions in the “holes” ...
0
votes
1answer
104 views
Melting point of crystalline solids
Why crystalline solids have sharp melting points but melting point of amorphous solids vary within a range?
Is it because the interaction energy is equal between atoms of crystalline solids so they ...
0
votes
1answer
62 views
Why are crystalline solids anisotropic? [closed]
Why crystalline solids are anisotropic whereas amorphous solids are isotropic?
Is it because in crystalline solids, X, Y and Z dimensions vary, but so does in amorphous.
Please write as simple as ...
0
votes
1answer
185 views
Are clathrates and interstitial compounds the same thing?
In the book$\ce{^{[1]}}$, it's given that clathrates are compounds in which gases are entrapped within cavities of crystal lattices of certain organic or inorganic compounds. Interstitial compounds ...
1
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0answers
19 views
Unit cell in a hexagonal closed pack structure
My textbook says that there are only 14 possible 3D lattices(Bravais Lattices).
One of these 14 lattices is a hexagonal lattice in which only a primitive variation is given to be possible.
But then I ...
0
votes
1answer
71 views
Cation-anion radius ratio of manganese difluoride
How to determine the cation-anion radius ratio for $\ce{MnF2}?$
I tried to calculate the $r_\mathrm{c}/r_\mathrm{a}$ ratio using the relationships:
$$2r_\mathrm{c} = c$$
and
$$(2r_\mathrm{c} + 4r_\...
1
vote
0answers
28 views
Sphalerite type structure
There are binary diamond type structures for example S and Zn form sphalerite. I thought the reason this formed was because of the big difference in the radii of the atoms that allows the smaller atom ...
1
vote
1answer
63 views
Is there a crystal structure of ammonia in ionic form?
Like solid $\ce{PCl5}$, does solid $\ce{NH3}$ exist as $\ce{[NH4+][NH2-]}$ (i.e. ammonium amide)?
1
vote
0answers
64 views
Why is liquid germanium denser than solid germanium?
Why are some elements like Ge and Si have liquids denser than their solids? In water it is explainable by H bonding, but no H bonds or such are there in Ge and Si.
Well, I want an explanation about ...
1
vote
1answer
136 views
Does a unit cell have to contain a whole number of atoms?
I was given this problem recently to compute the number of ions in a unit cell of ferrous oxide $\ce{FeO}$. The data given was:
Side length $a = \pu{5 Å}$
Density $d = \pu{4 g/cc}$
Using the formula ...
-4
votes
1answer
174 views
Why does Xenon Hexafluoride exist as [XeF5+][F-] and not [XeF5+][XeF2-] in the solid state [closed]
I already referred to this similar question but it yielded no explanation for the reason. Cations and anions of similar sizes stabilize each other through lattice energy effects in the solid state. ...
4
votes
1answer
93 views
Fractional index in a chemical formula of metal oxide
I have just read an article in which they used $\ce{WO3}$ and $\ce{WO_{2.9}}$ as precursors, whose objective was to form $\ce{WS2}$, in an atmosphere of argon by CVD. In one boat there is the powder ...
2
votes
0answers
79 views
Data-processing pipeline for protein x-ray crystallography: uncertain of terminology and order of procedures [closed]
Background: I am trying to get an overview of the data-processing pipeline for solving protein structures by x-ray crystallography, and in a very simple way understand what mathematical procedures are ...
0
votes
2answers
2k views
How to determine the chemical state of a reactant or product in a chemical equation?
I am asked this question:
Write a balanced equation, including state symbols, for this reaction:
$\ce{calcium + hydrochloric acid -> calcium chloride + hydrogen}$
I answered this:
$\ce{Ca(s) + ...
0
votes
0answers
130 views
Violation of Fajans' rule
According to Fajans' rules, greater charge in an ionic compound results in more covalent character. But why is it that sodium oxide is more covalent than magnesium oxide? Google says boiling point of ...
3
votes
1answer
336 views
Does the Fermi level correspond to the highest occupied energy level?
I know that, in the band structure of a solid, the Fermi level is the energy level at which there is a 50% probability of finding an electron (at thermodynamic equilibrium), and that it doesn't have ...
2
votes
1answer
61 views
Is an amorphous solid a single phase? [closed]
Amorphous solid possess short-range order but no long-range order (e.g. amorphous silica, the short-range order is originated from the tetrahedral bonding between Si and O). Is it possible to have ...
0
votes
2answers
109 views
Lattice enthalpy and ionic charater
As we move down in sulphates of group 2 their solubility decreases because there is a drastic decrease in hydration enthalpy as compared to decrease in lattice enthalpy.
Does the decrease in lattice ...
-2
votes
1answer
325 views
Unexpectedly low melting point of Aluminium
According to Wikipedia, the melting point of aluminium is 933.47K (660 oC) while the melting point of magnesium is 923K (650 oC), yet the melting point of sodium is merely 370.87K (98 oC).
With huge ...
2
votes
1answer
899 views
Why does aluminum chloride have a higher lattice energy than aluminum fluoride?
From the table below (source: McMurry's Chemistry [1, p. 212]), it is evident that $\ce{AlCl_3}$ has a higher lattice energy than $\ce{AlF3},$ even though $\ce{F}$ is smaller than $\ce{Cl}$. Why is ...
2
votes
1answer
105 views
Why does the colour of the same compound (e.g. magnesium nitride) differ?
When I am searching the colour of $\ce{Mg3N2}$ I came across photos showing different colours: greenish-yellow on Wikimedia,
and some other just yellow on some Google Images results.
I am eager to ...
3
votes
1answer
261 views
Structure of crystalline boron trioxide
I recently came across the statement
The structure of crystalline $\ce{B2O3}$ consists of $\ce{BO4}$ tetrahedra, two sets of which form two types of interconnected spiral chains, three $\ce{B-O}$ ...
1
vote
1answer
330 views
Why Frenkel defect does not impact the density of the solid?
The following text is from Chemistry Part I - Textbook for Class XII (NCERT), chapter "The Solid State", page 23, topic "1.9 Imperfections in Solids", sub topic "1.9.1 Types ...
3
votes
3answers
241 views
Why cobalt reacts favorably with nitrogen?
I used also iron, nickel, zinc, copper. However, cobalt gives the easiest and straight forward yield of nitrides (XPS and SAED verified).
It is so easy to get cobalt nitride that I don't even have to ...
3
votes
1answer
102 views
Is there a “Comprehensive Solid State” book?
We have Comprehensive Coordination Chemistry, Comprehensive Organometallics, Comprehensive Organic Synthesis and probably few other similar works that aim to do a wide review of recent works at the ...
9
votes
2answers
613 views
Software for generating a lattice from a unit cell for molecular crystals?
I am looking for a software package which can take a unit cell (and lattice parameters, etc.) and from that generate a crystal lattice. Ideally it will have functionality for orthorhombic, hexagonal, ...
0
votes
0answers
46 views
Validity of Maxwell-Boltzmann distribution for solids [duplicate]
Suppose there is a solid made of avogadro number of, say, aluminium atoms. This solid is kept at 273 K. According to Maxwell-Boltzmann distribution, all the particles or atoms will not have the same ...
3
votes
0answers
182 views
Electrical and thermal conductivity of graphite
I was reading about carbon family where it was mentioned that electrical conductivity of graphite increases with temperature while thermal conductivity decreases.
However, I could not find a suitable ...
0
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0answers
37 views
Is silicon-oxygen bond length non-uniform in quartz glass?
In many pictures depicting the molecular structure of quartz glass(In fact, almost every picture that represents amorphous state of any solid that I have seen), the bond lengths are non-uniform (I do ...
