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by aifooh7Keew6xoo 915 days ago
I assume this is discussing https://en.wikipedia.org/wiki/%CE%92-Carbon_nitride but the article neglects to identify the carbon nitride compound and the journal article doesn't seem to be available.
2 comments

The paper is available if you do a bit of digging. Following the name of the principal investigator goes to his site. The paper is not in his list of publications (one would think an academic would be a stickler about updating that?) but the news link leads to the institution's news story about that research¹. It's worth a read since it's more detailed than the New Scientist article without being as dense as the paper itself. At the bottom of the institution's news story is a link to the paper² which is freely available.

So if anyone is wondering what the "more chemically accurate name would be a mouthful refers to" (oP8-CN, tI14-C₃N₄, hP126-C₃N₄, and tI24-CN₂ were the carbon nitride forms produced) or what the "powerful explosive" mention refers to ("Energy density calculations were performed for the four C–N compounds with respect to decomposition into graphite and molecular nitrogen, at ambient conditions. They revealed that they have a high gravimetric energy density, comparable to or higher than that of TNT for oP8-CN, tI14-C₃N₄, hP126-C₃N₄,and for tI24-CN₂, a value even higher than for RDX..."), it's all there.

¹ https://www.ph.ed.ac.uk/news/2023/breakthrough-in-synthesis-...

² https://onlinelibrary.wiley.com/doi/epdf/10.1002/adma.202308...

I was reacquainted with Titanium Nitride care of a woodworker on YouTube the other day. It’s being used to protect tool surfaces from wear. Is that a coincidence or is there something special about nitrogen as a dopant?
https://en.wikipedia.org/wiki/Nitride

> Like carbides, nitrides are often refractory materials owing to their high lattice energy, which reflects the strong bonding of "N3−" to with metal cation(s). Thus, cubic boron nitride, titanium nitride, and silicon nitride are used as cutting materials and hard coatings. Hexagonal boron nitride, which adopts a layered structure, is a useful high-temperature lubricant akin to molybdenum disulfide.

Beyond that, when it comes to cutting tools in particular, there's often interesting solid phase and surface chemistry with layered gradients of oxynitrides forming at depth from the working interface that have similar properties to the base nitride and absorb energy through multiple phase changes and chemical dissociations before ultimate mass reduction, extending the life of the working surface

Cubic Boron Nitride [1] is another example.

[1] https://en.wikipedia.org/wiki/Borazon

I mean diamond is pure carbon, so if anything the nitrogen is making the substance in the article weaker.
> making the substance in the article weaker.

Less hard, to be more precise [1]. “Strong” and “weak” are way imprecise terms in engineering.

The simplest example is whether it’s strong under pressure (a brick is, a rope isn’t) or under tension (a rope is, a brick isn’t), but there are tons of other properties that are an indicator of strength of a material (https://en.wikipedia.org/wiki/Strength_of_materials), and this may beat diamond in some of them.

Reading https://en.wikipedia.org/wiki/Material_properties_of_diamond, diamond isn’t particularly tough, and we don’t really know its tensile strength, so this is less hard, but may have higher toughness or higher tensile strength.

[1] reading Wikipedia, even that isn’t simple: “There are three main types of hardness measurements: scratch, indentation, and rebound. Within each of these classes of measurement there are individual measurement scales. For practical reasons conversion tables are used to convert between one scale and another.”