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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36 views

Why water cools from outside to inside? [closed]

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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Doubt of solid state [closed]

A compound is formed by two elements Y and Z. Y ions in 2/3 of octahedral holes and 1/3 octahedral holes are vacant in closest packed array of Z ions. The formula of the compound is. (Options: Y2Z3, ...
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Can we determine if a compound is stoichiometric or non-stoichiometric from the chemical formula?

I often see alloyed perovskites are written in the format of $\ce{A'_xA''_{(1-x)}B'_xB''_{(1-x)}X_3}$. I am confused, if mole fractions of elements in A-site and B-site add up to 1 separately (E.g. $\...
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Stoichiometric defects in silver bromide

Stoichiometric defects (Schottky and Frenkel defects) in ionic crystals are formed due to irregularities in the ionic arrangement which maintain the stoichiometry and electroneutrality of the solid. ...
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“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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An octahedron is formed by joining the face centres of an FCC unit cell.The effective number of atoms present in the octahedron [closed]

An octahedron is formed by joining the face centres of an FCC unit cell.The effective number of atoms present in the octahedron is? i am not able to visualize , how it will be 1. there are one half ...
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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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53 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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1answer
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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
20 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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1answer
250 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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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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47 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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136 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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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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23 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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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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44 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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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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225 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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1answer
50 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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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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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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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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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
69 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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Why does tantalum and tungsten not form amalgam?

User @Poutnik has recently answered a question in which he/she quoted this statement from Wikipedia: Almost all metals can form amalgams with mercury, the notable exceptions being iron, platinum, ...
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209 views

The Verb for Polymorphism

How can you elegantly describe that a polymorphic substance changes its structure? It polymorphs It morphs It undergoes polymorphic transition It experiences a morphic change Or what ...
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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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420 views

Are chiral quasicrystals possible?

Quasicrystals are materials that have long-range atomic order but lack the translational symmetry of conventional crystals. All quasicrystalline tilings and packings I have read about thus far, whilst ...
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Effect of temperature and pressure on structure of solids

What is the effect of these conditions on the structure of solids? My book has the answer that confuses me. I got nothing about it. Can you please explain? The answer of the book is With the ...
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1answer
512 views

Chemical formula of a compound crystallized in a cubic lattice

Question In a cubic lattice of $\ce{XYZ},$ $\ce{X}$ atoms are present at all corners except one corner which is occupied by $\ce{Y}$ atoms. $\ce{Z}$ atoms are present at face centres. What is the ...
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52 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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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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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
60 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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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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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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Calculate the third and fourth nearest neighbours in bcc

My textbook has given data for third and fourth nearest neighbours to be 12 and 8 with distances $\sqrt{2}a$ and $\frac{\sqrt{11}a}{2}$. I have been able to calculate for the first and second ...
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1answer
105 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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807 views

Solid 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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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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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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How many tetrahedral and octahedral holes are there in a bcc unit cell?

When I tried to count, I found 24 tetrahedral holes (each formed by 2 body centers of 2 unit cells sharing a face and 2 vertices of the same edge of that face). As each hole is being shared by 2 unit ...
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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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273 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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The Limitation of Solid Phase Peptide Synthesis In Case of Polyglycine

I was wondering if I could use your experience and all the precautions you would like to recommend for a long peptide synthesis via SPPS. I've already got a low loading resin so this way I'll minimize ...
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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
136 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 ...
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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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