3 ms·

Then why do we have separate names for Graphite and Diamond? Same element, different molecular (crystalline) structures. If CuO25P6Pb9 can exhibit superconducti

by dcow 3y ago

Then why do we have separate names for Graphite and Diamond? Same element, different molecular (crystalline) structures. If CuO25P6Pb9 can exhibit superconducting properties, and reproduction attempts are failing, then there must be a specific isomer that needs to be achieved, the creation of which is not described in the LK-99 paper. I'm just trying to understand how to wade through this stuff, I could be wrong, and I dropped solid state physics because I hated it, but that's how I currently understand the situation. Edit: s/isomer/polymorph

jacquesm 3y ago
Same molecular structure entirely different crystal lattice. It is the formation that is different not the molecules. C = C. They are technically allotropes: https://en.wikipedia.org/wiki/Allotropy https://en.wikipedia.org/wiki/Allotropy And just like here that's a function of how the bulk carbon got to be formed, under extreme pressure and temperatures or less pressure and temperature. It's the recipe that makes the difference, not the ingredients.
- dcow 3y ago
  As far as I understand, we're saying the same thing. isomer /'aɪsəmər/ noun a compound that exists in forms having different arrangements of atoms but the same molecular weight I'm using isomer to refer to possible different arrangements of "the LK99 compound". I see you're saying allotropes refers to diamond vs carbon (allotrope referring a single element vs isomer referring to compound). That raises a question, what's the name for different crystalline structures of the same compound? Is that still an isomer or something different? I'm out of my element here.
  - jacquesm 3y ago
    An isomer can have different valences but still have the same overall chemical formula. So just for an example (I have no idea how to put a tetrahedron in a comment :) ) a chain of C-C-C-C and C-C=C-C (which you likely can not synthesize) would be an isomer but C-C-C-C in one crystal lattice versus C-C-C-C in another crystal lattice would be allotropes. The carbon in graphite sits in sheets (hence the possibility to form graphene), whereas the carbon in a diamond always forms three dimensional lattices. edit nah: bad example, sorry, I can't find a good way to visualize this in text the 2nd C-C-C-C chain should have the last C dangling from the 2nd down. edit2: examples are wrong, I should have used a more complex molecule for the isomer and the carbon can have either three or four other carbons hanging of it for the allotrope. tricky...
    - dcow 3y ago
      Just double checking, the definitions I'm finding for allotrope are specific to a single element. allotrope /'ælə,troʊp/ noun a structurally different form of an element I'm having trouble finding allotrope used to refer to different forms of a compound. https://www.differencebetween.com/difference-between-allotrope-and-vs-isomer/ https://www.differencebetween.com/difference-between-allotro...
      - jacquesm 3y ago
        Yes, you're right, I should have used a more complex example for an isomer.
  - cyberax 3y ago
    Isomers are structurally different. Allotropes refer to variations of the same element. You're looking at the word "polymorph": "(chemistry, geology) Any substance or mineral that forms different types of crystal."
    - dcow 3y ago
      Thank you.

by dcow 3y ago

jacquesm 3y ago

Same molecular structure entirely different crystal lattice. It is the formation that is different not the molecules. C = C. They are technically allotropes: https://en.wikipedia.org/wiki/Allotropy https://en.wikipedia.org/wiki/Allotropy And just like here that's a function of how the bulk carbon got to be formed, under extreme pressure and temperatures or less pressure and temperature. It's the recipe that makes the difference, not the ingredients.

dcow 3y ago
As far as I understand, we're saying the same thing. isomer /'aɪsəmər/ noun a compound that exists in forms having different arrangements of atoms but the same molecular weight I'm using isomer to refer to possible different arrangements of "the LK99 compound". I see you're saying allotropes refers to diamond vs carbon (allotrope referring a single element vs isomer referring to compound). That raises a question, what's the name for different crystalline structures of the same compound? Is that still an isomer or something different? I'm out of my element here.
- jacquesm 3y ago
  An isomer can have different valences but still have the same overall chemical formula. So just for an example (I have no idea how to put a tetrahedron in a comment :) ) a chain of C-C-C-C and C-C=C-C (which you likely can not synthesize) would be an isomer but C-C-C-C in one crystal lattice versus C-C-C-C in another crystal lattice would be allotropes. The carbon in graphite sits in sheets (hence the possibility to form graphene), whereas the carbon in a diamond always forms three dimensional lattices. edit nah: bad example, sorry, I can't find a good way to visualize this in text the 2nd C-C-C-C chain should have the last C dangling from the 2nd down. edit2: examples are wrong, I should have used a more complex molecule for the isomer and the carbon can have either three or four other carbons hanging of it for the allotrope. tricky...
  - dcow 3y ago
    Just double checking, the definitions I'm finding for allotrope are specific to a single element. allotrope /'ælə,troʊp/ noun a structurally different form of an element I'm having trouble finding allotrope used to refer to different forms of a compound. https://www.differencebetween.com/difference-between-allotrope-and-vs-isomer/ https://www.differencebetween.com/difference-between-allotro...
    - jacquesm 3y ago
      Yes, you're right, I should have used a more complex example for an isomer.
- cyberax 3y ago
  Isomers are structurally different. Allotropes refer to variations of the same element. You're looking at the word "polymorph": "(chemistry, geology) Any substance or mineral that forms different types of crystal."
  - dcow 3y ago
    Thank you.