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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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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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 ...
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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.
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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 ,\...
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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+ ...
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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, ...
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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=...
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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 (...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 (...
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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 ...
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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) ...
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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, ...
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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 ...
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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 ...
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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 ...
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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 ...
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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” ...
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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 ...
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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 ...
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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 ...
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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 ...
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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_\...
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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 ...
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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)?
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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 ...
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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 ...
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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. ...
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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 ...
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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 ...
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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) + ...
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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 ...
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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
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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 ...
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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 ...
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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 ...
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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 ...
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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
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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 $\ce{B-O}$ ...
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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 ...
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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 ...
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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 ...
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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, ...
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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 ...
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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 ...
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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 ...

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