For the alternative theorists:

[leopold]

is diamond unique in this property?
if you add an atom to ANY compound it will no longer be that compound, but diamond seems to be exactly that.

edit:
apparently it is,
The diamond is the best known and the most heavily marketed gemstone. Like graphite, lonsdaleite ("hexagonal diamond"), and the fullerenes, a diamond is an allotrope of carbon and, no matter what its size, each diamond can be considered to be a single molecule of carbon.
https://dendritics.com/scales/diamond-properties.asp

 

[exchemist]

ok.
the smallest unit of ANY material is either an atom or a molecule.
the smallest unit of table salt is one molecule consisting one each of sodium and chlorine.
now, if you have an unknown material and you get an empirical formula that doesn't resolve to integers, what does this mean?
this is what i based my opinions on.

I think you can get this with some alloys and materials "doped" with impurities. But these are not generally considered discrete chemical compounds. Real life minerals and things do not always conform to the neat rules of stoichiometry we have in our chemistry labs.

 

[exchemist]

is diamond unique in this property?
if you add an atom to ANY compound it will no longer be that compound, but diamond seems to be exactly that.

edit:
apparently it is,
The diamond is the best known and the most heavily marketed gemstone. Like graphite, lonsdaleite ("hexagonal diamond"), and the fullerenes, a diamond is an allotrope of carbon and, no matter what its size, each diamond can be considered to be a single molecule of carbon.
https://dendritics.com/scales/diamond-properties.asp

Leopold I really wouldn't push this if I were you. I said from my first intervention in this discussion that extended arrays or lattices are an alternative to molecules. They are not molecules, they are something else. I do not think it is at all helpful to describe these structures as molecules. Chemists at any rate do not generally do so.

 

[paddoboy]

Leopold I really wouldn't push this if I were you. I said from my first intervention in this discussion that extended arrays or lattices are an alternative to molecules. They are not molecules, they are something else. I do not think it is at all helpful to describe these structures as molecules. Chemists at any rate do not generally do so.

And it in no way invalidates the certainty of Evolution and Abiogenesis, from whence this more detailed discussion has sprung.

 

[Beer w/Straw]

I looked up electrolysis, methane lakes on Titan, and now looked up gold.

Can gold can exist as an atom by itself, usually?

:EDIT:

Yes, my chemistry is bad. Lead is to my knowledge the least reactive. But they don't store lead in Fort Knox.

 

[leopold]

I think you can get this with some alloys and materials "doped" with impurities.

the best examples are semiconductor chips, transistors, that sort of thing.

But these are not generally considered discrete chemical compounds.

probably a "solid mixture" would describe it best.

Real life minerals and things do not always conform to the neat rules of stoichiometry we have in our chemistry labs.

i assume this basically means "balancing the equation".

edit:
heh, yeah, i had to look it up,
en.wikipedia.org/wiki/Stoichiometry

 

[leopold]

Leopold I really wouldn't push this if I were you. I said from my first intervention in this discussion that extended arrays or lattices are an alternative to molecules. They are not molecules, they are something else. I do not think it is at all helpful to describe these structures as molecules. Chemists at any rate do not generally do so.

but they ARE molecules, in the case of pure diamond single molecules.
a grain of table salt is different, it's composed of several of the same molecule NaCl.
you are correct in saying it's something that isn't discussed much.

 

[Trippy]

is diamond unique in this property?
if you add an atom to ANY compound it will no longer be that compound, but diamond seems to be exactly that.

edit:
apparently it is,
The diamond is the best known and the most heavily marketed gemstone. Like graphite, lonsdaleite ("hexagonal diamond"), and the fullerenes, a diamond is an allotrope of carbon and, no matter what its size, each diamond can be considered to be a single molecule of carbon.
https://dendritics.com/scales/diamond-properties.asp

No diamond is not unique. Calcium fluoride is white. The beer posted earlier was pink, probably because of manganese contamination. There's also F centers where a negative ion is replaced by a free electron. And then there's point defects and diocations to consider, not to mention inclusions...

 

[Trippy]

Leopold I really wouldn't push this if I were you. I said from my first intervention in this discussion that extended arrays or lattices are an alternative to molecules. They are not molecules, they are something else. I do not think it is at all helpful to describe these structures as molecules. Chemists at any rate do not generally do so.

Seconded.

 

[Beer w/Straw]

Metals have valence electrons, diamonds do not.

My question, I hope, wasn't actually that stupid?

 

[Write4U]

I looked up electrolysis, methane lakes on Titan, and now looked up gold.

Can gold can exist as an atom by itself, usually?

:EDIT:

Yes, my chemistry is bad. Lead is to my knowledge the least reactive. But they don't store lead in Fort Knox.

I used to have the whole series of NOVA "making stuff smaller". I cannot stream it anymore but below is excerpt that may be of interest:

DAVID POGUE: But it doesn't look gold, it looks pink.

MIKE TUFFEY: No, gold gives you pink.

DAVID POGUE: Gold gives you pink?

MIKE TUFFEY: Gold gives you pink.

DAVID POGUE: Why would that be?

MIKE TUFFEY: Ah, you would need to talk to a chemist on that one.

DAVID POGUE: I plan to do that.

Same answer. I'm 0-for-2 with the stained glass people.

So I went to Canterbury Cathedral, and I actually spoke to the guy who makes the glass, and the lady who does the repairs on those windows, and they said sure enough, they add gold to the glass to make it red. It doesn't make any sense, and you know what they told me? "We have no clue." But you're the scientis, man, you should, you should be able to explain why gold makes red.

CHAD MIRKIN (chemist): Well, it turns out that if you can control the size of a gold particle, if you can shrink it to this nanometer-length scale, you have completely different optical properties. Gold is no longer gold when taken to the 13-nanometer size, it's ruby red in color.

DAVID POGUE: When light rays hit a colored material, some colors are absorbed and some are reflected. That's why roses are red and violets are blue. Many metals, like gold and silver, reflect most of the colors in visible light, which is why they can be polished to shine like mirrors. But when a particle of gold is made very small, below 100 nanometers, 100 billionths of a meter, the particle begins to absorb shorter wavelengths of light, toward the blue end of the spectrum. The smaller the particle, the more blue is absorbed and the redder it appears.

But it gets even stranger, because not only size matters, shape does too.

Each of these vials contains water with silver nanoparticles dissolved in it. The only difference between them is the shape of the particles. In this test, silver rods give you yellow; silver triangles, green; silver prisms give you blue.

If metals behaved like this in our big world, then just changing the size or the shape of your car would alter its color.

Chad sees tremendous potential in this weird nano-phenomenon.

CHAD MIRKIN: With almost an infinite number of possibilities, you no longer have to take what nature gives you. You can adjust color simply by becoming a nano-architect.

DAVID POGUE: Scientists call this strange property of small materials "structural color." The living world figured this out millions of years ago. Structural color on the nano-scale creates the iridescent pigments in butterfly wings, beetle shells and peacock feathers.

Well, why do we care? I mean cool, little tiny gold particles are really red. I mean how does that help mankind?

CHAD MIRKIN: Well, the reason we care is that once you discover new properties, those new properties almost always lead to new applications.

DAVID POGUE: There are already a number of medical applications. Chad Mirkin has developed a technology that harnesses the unique properties of gold and silver nanoparticles to test the genetic variations in patients.

Sequencing D.N.A. is expensive and time-consuming, but Chad's revolutionary test takes less than two hours.

http://www.pbs.org/wgbh/nova/tech/making-stuff.html#making-stuff-smaller

 

[leopold]

No diamond is not unique. Calcium fluoride is white. The beer posted earlier was pink, probably because of manganese contamination. There's also F centers where a negative ion is replaced by a free electron. And then there's point defects and diocations to consider, not to mention inclusions...

yes but diamond exhibits the following property:
the chemical addition of an element (carbon in this instance) does not change the chemical properties of the compound.
it also doesn't change the status of the molecule.
maybe this is why crystallography is a separate area of study.
i never really thought about this before.

about gold,
in my opinion all elements can exist as single atoms.
some elements quickly combine with themselves to form molecular elements. (for example H2,O2)

 

[Beer w/Straw]

I'll open my chemistry textbook...

 

[Trippy]

Metals have valence electrons, diamonds do not.

My question, I hope, wasn't actually that stupid?

Everything has valence electrons. The difference between metals and diamond is in metals they are free, but in diamond they are all tied up in covalent bonds. The difference beyween graphite and carbon is that some of those covalent bonds are delocalised and the electroms behave as if they were free.

 

[Beer w/Straw]

I meant metal can bend.

I am tired as well, so... I may not be making much sense.

 

[Trippy]

yes but diamond exhibits the following property:
the chemical addition of an element (carbon in this instance) does not change the chemical properties of the compound.
it also doesn't change the status of the molecule.
maybe this is why crystallography is a separate area of study.
i never really thought about this before.

about gold,
in my opinion all elements can exist as single atoms.
some elements quickly combine with themselves to form molecular elements. (for example H2,O2)

I'm not sure what your point is here? The same is arguably true for any elememt. The addition of more of that elememt doesn't change its chemical properties. Likewise if I take sldium chloride and add more sodium chloride to it notbinv changes.

But when you start incoporating other elements things change.
Unpaired nitrogen atoms give canary diamonds.
Boron give blue, grey, or slate.
Hydrogen can give rise to chameleon diamonds whose colours change depending on conditions and lighting.
Green is due to the presence of F-centers.
Pink and red are caused by lattice distortions, and orange is probably caused by this combined with nitrogen.

 

[Trippy]

I meant metal can bend.

I am tired as well, so... I may not be making much sense.

As I recall the malleability of metals is because they are essential metal ions embedded in a sea of electrons. Unlike ionic or covalent compounds the metal atoms can slide past each other.

 

[leopold]

I'm not sure what your point is here? The same is arguably true for any elememt.

yes, you can chemically add elements to compounds.
the properties of that new compound are different than the old compound, plus you wind up with a different molecule..
adding a carbon to a straight chain changes the chemical properties.
chemically adding sodium or chlorine changes the properties of table salt.
this apparently isn't true with diamonds.
chemically adding more carbon to the mix changes nothing except the size and mass.

The addition of more of that elememt doesn't change its chemical properties.

i understand that, it's the reason i specifically mentioned chemical addition.

 

[exchemist]

Metals have valence electrons, diamonds do not.

My question, I hope, wasn't actually that stupid?

This is incorrect. The term "valence" electron applies to any electron that is available to participate in bonding.

Chemical bonds are broadly of two types: ionic and covalent (though in practice these represent the "pure" extreme types and a range of "mixed", part-ionic, part covalent bonds is found in many compounds.)

In metals, the valence electrons are delocalised from their parent atoms and form a "sea" of electrons in which the net +ve charged atomic ions, or "cores", are arranged in a lattice structure. (So no molecules here, Leopold.)

In a non-metallic substance such as diamond or quartz (silica, SiO2) there is a again an extended lattice (so no molecules Leopold) but built of a network of covalent bonds between the atoms. These covalent bonds form due to sharing of valence electrons between atoms, in the molecular orbitals that arise due to the presence 2 or more centres of nuclear charge.

And in solid non-metallic molecular substances (yellow sulphur has been mentioned) the atoms are strongly covalently bonded into molecules, which are then in turn weakly bound into a solid lattice by van der Waal's forces ("dispersion" forces, that arise from fluctuating, temporary dipoles due to the motion of the electrons in adjacent atoms).

 

[Trippy]

yes, you can chemically add elements to compounds.
the properties of that new compound are different than the old compound, plus you wind up with a different molecule..
adding a carbon to a straight chain changes the chemical properties.

No it doesn't - If I add a CH[sub]2[/sub] to Ethane I get propane which has the same chemical properties but different physical properties.

chemically adding sodium or chlorine changes the properties of table salt.

I didn't say sodium and chlorine, I said Sodium and chloride. And if I had more sodium chloride nothing changes.

chemically adding more carbon to the mix changes nothing except the size and mass.

Correct.

i understand that, it's the reason i specifically mentioned chemical addition.

Specifying chemical addition is meaningless. And it still isn't exclusively true of diamonds and carbon. If I had more Silica to a quartz crystal I have to add them by forming a covalent bond to what's already there. Doing so changes nothing except the size and mass.