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7
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1answer
270 views

Is BCl₅ possible?

Is $\ce{BCl5}$ possible? I saw it in book. As far as we can see there is no way to get 5 chlorine atoms with boron.
4
votes
2answers
61 views

If salt crystals make a cube shape, what is this 'X' marking?

I am an amateur, with very little professional chemistry knowledge. I was doing a demonstration / experiment with my 6 year old child. We took very warm normal tap water, and dissolved into it a ...
1
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1answer
38 views

Chemical bonding - lattice energy

Question: Why is ionic lattice energy inversely proportional to the radius of the atom? Most heterogeneous covalent molecules are polar to some extent. The degree of polarity, or the dipole moment, ...
0
votes
0answers
12 views

Polymer Crystallinity

See the following question: I think the answer is A because of the hydrogen bond in the side group, thus the degree of secondary bonding between parallel chain segments is higher. Is my thinking ...
5
votes
0answers
42 views

How does the crystal know where to stop stacking the unit cells?

I tried to make different crystals in the cubic system by stacking cubes in a 3d software. However I need to tell the software where to skip rows or stop stacking the unit cells in a specific ...
1
vote
1answer
34 views

How do we know the size of atoms in body centered cubic system?

I'm told that in the normal cubic system there are $\frac18$ of an atom at each corner and these atoms' radius are such that $a = 2r$ ($a$ is the lattice constant, $r$ radius of an atom). In bbc ...
5
votes
3answers
317 views

Are metallic/ionic bonds weaker than covalent bonds? I was taught the opposite. Now I'm confused

In mineralogy class, I was taught that metallic and ionic bonds are weaker than covalent bonds and that's why quartz and diamond have such a high hardness value. However, in organic chemistry class, I ...
1
vote
1answer
85 views

Why do NaHCO₃ and KHCO₃ have different crystal structures?

Why do $\ce{NaHCO3}$ and $\ce{KHCO3}$ have different crystal structures? We had this in a test today and this got me stumped... My questions are: Do $\ce{NaHCO3}$ and $\ce{KHCO3}$ possess ...
1
vote
1answer
58 views

Bonding, multiplicity and quantum chemistry for FeP$_2$

I'm trying to do some quantum chemical calculations for the linear molecule FeP$_2$ in the gas phase as well as its crystal (orthorhombic symmetry like here). I am lead to believe that in both cases ...
0
votes
0answers
26 views

How to determine mineral properties based on chemical formula?

I need to learn a bunch of minerals and their properties. What I want is some sort of rule which helps me deduce color, crystal system, luster etc. I know that different kind of ions give specific ...
1
vote
1answer
76 views

How to memorize 7 crystal systems?

Is there any trick to memorize the angles and sides of 7 crystal systems of crystalline solids? 1. Cubic 2. Tetragonal 3. Orthorhombic 4. Monoclinic 5. Hexagonal 6. Rhombohedral or Trigonal 7. ...
1
vote
1answer
59 views

What is the minimum distance of Rubidium and Iod ions in a centered cube?

I have a problem to visualize the following assignment: What is the minimum distance between $\ce{Rb^+}$ and $\ce{I^-}$ ions if radius of $\ce{Rb^+}$ is ${1.49\cdot10^{-10}}~\mathrm{m}$ and radius ...
6
votes
3answers
488 views

How many Ga atoms are connected to one As atom in solid state Gallium arsenide

Let's start straight away. In this book on page 4 Gallium arsenide's bond structure is shown like this: $As$ is shown making $5$ covalent bonds. Recently I came across this book. The bond structure ...
1
vote
1answer
86 views

Hexagonal unit cells

I know 3 types of unit cells, the simple cubic, the body centered and the face centered. But what is a hexagonal unit cell, and why does it have a hexagon base while others are all cut into a cubic? ...
1
vote
0answers
32 views

Why is there one octahedral and two tetrahedral positions for every anion in a close packed structure?

I'm reading about ionic crystal structures with planes of close-packed anions and the interstitial sites for cations. There are two types of interstitial sites: tetrahedral and octahedral. That makes ...
1
vote
2answers
61 views

Why are cations ordinarily smaller than anions?

I'm reading on ionic crystal structures and am confused by this from my textbook: Because the metallic elements give up electrons when ionized, cations are ordinarily smaller than anions I ...
3
votes
2answers
125 views

Is a diamond a single molecule?

Assuming a perfect diamond with no impurities. Would this diamond considered to be a single large molecule? Browsing the interweb I found several opinions about this but did not find a clear Yes or ...
1
vote
1answer
156 views

is there any mnemonic for the AXE method?

Is there any mnemonic that helps remembering the names of the different geometries (Shapes) that we obtain from applying the AXE method ?
3
votes
2answers
71 views

Is it possible to cut yourself on pyrite?

I am planning an RPG adventure where the characters might end up getting a large cubic lump of "gold", which in reality, as you might have guessed, is in fact pyrite. I also wanted to plan for the ...
1
vote
2answers
105 views

Why does ZnO turn yellow when it is hot?

Why does ZnO's color become yellow when it is hot? I have read that it is because of physical properties, but I need a more elaborate explanation.
1
vote
0answers
116 views

How do you determine a chemical formula given the molecule's crystal structure?

How do you determine the chemical formula of a compound given its crystal structure?
0
votes
0answers
267 views

How to calculate lattice parameter only using planes and d spacing

I am trying to find lattice parameter of a hexagonal crystal, usually I use cellcalc for calculating lattice parameter of a crystal structure. In that software it asks only two queries, one is details ...
1
vote
1answer
41 views

Rapidly cooling Aluminum vapour to solid state?

What sort of a microstructure would you get on bubbling Aluminium vapors through a large tank of Helium?Would it be a glassy microstructure and/or would you get nano-powders? and/or a new crystal ...
2
votes
0answers
73 views

Bond Lengths in FCC, BCC and HCP Structures

I was wondering what the crystal structures of FCC, BCC and HCP actually look like, and where atoms are placed in their configuration? Specifically I'm looking at elemental nickel, iron and cobalt ...
0
votes
1answer
4k views

What's the difference between alpha-glucose and beta-glucose?

What's the difference between $\alpha$-D-glucose and $\beta$-D-glucose? Are they isoforms? Or do they differ in their elemental composition?
2
votes
3answers
433 views

What's up with SiO2 being tetrahedral?

If silicon dioxide tends to form a crystal lattice with four Os around a central S, why isn't the molecular formula $\ce{SiO4}$ then? I'm confused why it's unique in that its molecular formula doesn't ...
0
votes
1answer
108 views

Wasn't Rutherford's assumption of gold foil to be made of single layer wrong?

My teacher taught about Rutherford's gold foil experiment today. Sir said that, Rutherford used gold foil of thickness $10^{-7}$ m and concluded atom to be of size $10^{-10}$ m. Sir also said that ...
4
votes
2answers
288 views

What is the edge of a diamond like?

The chemical structure of a diamond is defined as an endless lattice in which each carbon atom is covalently bonded to four other carbon atoms situated at the four ends of a tetrahedron. But of ...
0
votes
1answer
16 views

What conditions to use to crystallise Equine Myoglobin?

What are the crystallisation conditions for Equine Myoglobin? I've tried repeating some from the PDB but no success.
5
votes
2answers
24 views

What does the Sm5Ge4 orthorhombic structure look like?

I see tons of papers referencing this structure but none show what it looks like.
2
votes
1answer
42 views

Why polymorphs form?

We always hear about the different arrangements of molecules that lead to the formation of polymorphs, my question here is why would a polymorph form in the first place? The material was given enough ...
1
vote
1answer
64 views

Relating a compound's radii and unit cell dimensions

We're asked often to calculate the density of a crystal, and there is a known formula for that related to the unit cell volume. Now, for simple geometric structures such as the bcc structure (and ...
0
votes
1answer
179 views

How do point defects in a crystal relate to Entropy?

I am interested in Non-Stoichiometry and how it relates to crystal structures; In particular I wish to learn about surfaces of metal oxides. I am aware that point defects in such crystals are a result ...
0
votes
2answers
5k views

How to calculate crystal field stabilisation energy?

How to calculate it? I know that it depends on the coordination compound and the number of electrons present in t2g and eg orbitals and the final answer is expressed in terms of crystal field ...
8
votes
0answers
552 views

Stoichiometric defects in ionic crystal?

The stoichiometric defects (Schottky and Frenkel defects) in ionic crystals are formed due to irregularities in ionic arrangement all the while maintaining the stoichiometry and electric neutrality. ...
1
vote
1answer
59 views

Liquid crystal current flow

Sorry, maybe some terms used in the question are not correct and may be this is a trivial question, but I'm not a chemist I am a computer scientist. In a liquid crystal cell used for LCD the ...
7
votes
1answer
787 views

Is it possible to save an insoluble snowflake?

In The Big Bang Theory Season 3 Episode 1 "The Electric Can Opener Fluctuation" Leonard gives Penny a snowflake that will never melt. He said some type of chemical gas name when he try to explain, ...
4
votes
2answers
324 views

Use of Sulphuric Acid in Crystallization

I read that:- Take a cupful of water in a beaker and add a few drops of dilute sulphuric acid. Heat the water. When it starts boiling add copper sulphate powder slowly while stirring ...
1
vote
1answer
270 views

Find the number of copper spheres in a box

A box contains a mixture of small copper spheres and small lead spheres. The total volume of both metals is measured by the displacement of water to be 420 cm³ and the total mass is 5.4 kg. What ...
1
vote
1answer
533 views

Effect of dopant size on XRD peak shift

If we add an impurity atom (doping) to the crystalline struture of another material and take the XRD of the doped material what kind of peak shift can we expect. For the better description of my ...
2
votes
1answer
184 views

How much heat is required to dehydrate a hydrate?

If I have a hydrate, such as copper (II) sulfate pentahydrate, $\ce{CuSO_4 \cdot 5H_2O}$, what is the amount of heat to required to dehydrate it? I assume that it is equal to or greater than the ...
2
votes
1answer
61 views

Structure of N₅P₃?

What is the structure of the molecule N₅P₃? N₅P₃ is not documented online so could anyone please say the structure of the molecule: How many ligands does each Phosphorous atom have? How many ...
3
votes
3answers
97 views

Which gems can be prepared on a small scale basis?

I am interested to know the following: Which gems can be prepared at home(without sophisticated instruments) ? What will be the quality(appearance) of the product for a certain method ? I want ...
4
votes
2answers
887 views

Confusion in unit cells of crystal system

Unit cells are divided into two main types Primitive Non-primitive Primitive includes simple cubic lattice whereas non-primitive includes fcc bcc end centered.. Among the seven types of crystal ...
1
vote
1answer
121 views

Crystallization of solutions and liquids

The process of crystallization of a liquid or any solute occurs when its concentration exceeds the maximum concentration which the solvent can carry or when the temperature drops below the freezing ...
2
votes
2answers
176 views

Create my own solar cells?

How would I grow my own and build functional solar cells? I've read and researched that they're mostly a crystal structure of something like silicon. I would assume I'd be able to grow my own crystals ...
1
vote
1answer
125 views

How to make artificial diamond?

i always knew that carbon can not be turned to diamond artificially but while watching a video i learned that a diamond can be made from the ashes of a man , how is this possible? sorry if i put the ...
1
vote
0answers
79 views

How do octahedral seed crystals yield polyhedral Cu2O crystals?

In an article I am trying to understand, the following occurs: (summarized below) Synthesis of octahedral $\ce{Cu_2O}$ seeds:In a typical synthesis, 2.9946 g of $\ce{Cu(CH_3COO)_2}$ was dissolved ...
1
vote
1answer
774 views

Smallest nearest neighbor distance among elements

Of all the elements in periodic table, which one has smallest nearest neighbor distance? I tried searching on net, but could not find any reference. My earlier guess was one which goes into FCC with ...
2
votes
3answers
2k views

Normal Spinel and Inverse Spinel

According to my notes, [OCTAHEDRAL SITE STABILIZATION ENERGY (OSSE)], sterical effects and electronic effects in stability create a confusion in this theory. However, we are able to solve this problem ...