# Tag Info

Accepted

### Contribution of Tetrahedral and Octahedral voids in HCP

I cannot find anywhere.. Couldn't find? You can figure it out on your own, with me, right now. Disclaimer: By "hexagonal unit cell" I assume you mean hexagonal prism, which comprises of 3 primitive ...
• 2,925

### How can brass still be made even though the crystal structures of zinc and copper are not the same?

The $\ce{Cu-Zn}$ phase diagram is, to put it mildly, complicated. (source) See that wide area denoted $\alpha\rm (Cu)$? Now, when we add a little amount of one metal into the crystal lattice of ...
• 31.2k
Accepted

### What makes Gorilla Glass more durable with each generation?

Are there other ways of "chemical strengthening" besides cationic exchange that can be utilized to strengthen the glass, keeping it flexible and less fragile at the same time? In a word: No. To ...
• 12.6k

### How to calculate the height of an hcp lattice?

To calculate the height of a unit cell, consider a tetrahedral void in an hexagonal closed packing arrangement. It can be imagined as a 3 solid spheres touching each other and at the center-point, you ...
• 4,144
Accepted

### Will a solid object lose or gain atoms on standing over time (without being acted upon by external influences)?

Short answer: Yes they do. Firstly, you need to arrive at a proper definition for an "object". Why you ask? Because it would otherwise present philosophical problems which become apparent when we ...
• 18.7k

### How are the number of tetrahedral voids twice the number of octahedral voids in a CCP structure?

To be precise, if in a close packed structure (ccp or fcc) there are $n$ atoms or ions then the number of octahedral voids and tetrahedral voids will be $n$ and $2n$ respectively. For example, there ...
• 1,108
Accepted

### For a given packing (hcp, fcc, bcc), which ions occupy the corners and which occupy the faces or centers?

The actual answer is that it doesn't matter. For many of the 1:1 solid-state structures, either the cations or the anions may be considered to be at the vertices (i.e. corners) of the unit cell. By ...
• 71.4k

### How can brass still be made even though the crystal structures of zinc and copper are not the same?

While molten, copper and zinc (and tin) are miscible. As the alloy cools and crystalizes, the metals do indeed separate, forming grain boundaries. These inclusions "pin" slippage between ...
• 33.3k

### What does β stand for in β-potassium zirconate?

They signify one polymorph (the beta polymorph) of barium zirconate. Allotropy is the property of some chemical elements or compounds to exist in two or more different forms in the same physical state ...
• 25.9k

### What is "chemical pressure"?

External and internal pressure To study the effect of pressure on properties of a solid, is equivalently to learn how changes in volume transform physical parameters. For external pressure at ...
• 7,050

• 68.2k

### Why are there exactly 5 types of two-dimensional lattices, and what distinguishes them?

First, about the black lines. I think they are helpful for the hexagonal and the rhombic lattice. For the hexagonal system, it shows you the hexagons. One hexagon contains exactly the same space as ...
• 40.7k
Accepted

### What are some materials that expand a lot proportionally to heat?

You are looking for thermal expansion and its coefficient. Of course such tables, and diagrams exist (source) as it is of relevance in daily live. Thermometers based on liquid mercury, or alcohol, ...
• 30.1k

### Why doesn't tantalum and tungsten form amalgam?

Imagine a lump of a metallic element in close contact with an equal amount of liquid mercury. Amalgamation might proceed to some degree if the metallic element has an even higher surface tension than ...
• 14k

### Why is sea salt coarse?

The method of production of sea salt usually involves bulk evaporation of seawater. This allows the salt to crystallise and due to it's bigger size it is sold without much processing. On the other ...
• 471

### Why is diamond not the most dense substance?

There is no general relation between hardness and density. One thing is the packing and bonding character ( what matters mostly for hardness), other is the idealized atomic ball radius and the atomic ...
• 42.3k
Accepted

### "Fireblob" in KO₂ and PCl₅ reaction

Here's my best guess at the play-by-play. $\ce{PCl5}$ is a solid with a relatively low melting point (160 °C) and high volatility (sublimes at 167 °C). When the solid $\ce{KO2}$ gets dropped on the \$\...
• 28.9k

### What makes Gorilla Glass more durable with each generation?

To really answer this, you need to characterize the glass in terms of its properties, and not something like its ability to resist being scratched. Scratch resistance is a behaviour, and not a ...
• 254