Whats the difference?

[shygurl475]

I'm new here and i'm kind of stupid so please be nice to me lol.

Anyways, here's my question:

 

Is Cl2 a covalent compound or a molecular compound?

What's the difference between them?

Thanks

[insane_alien]

Both. you can't get a compound without it being molecular.

 

Compounds can be classed by the primary type of bonding, these are covalent, ionic or metallic and all the intermediate stages.

[nitroglycol]

Is it really accurate to call it a compound at all? Yes, it has two atoms, but they're both the same element.

[insane_alien]

while in normal everyday usage it would be defined as an element it can technically be classed as a compound. at the very least a molecule.

[nitroglycol]

Well, it's a molecule for sure, but most definitions of a compound say that it contains two or more elements. I guess there might be some ambiguity in the definition though.

 

Both. you can't get a compound without it being molecular.

 

Actually, I have to quibble with this too; sodium chloride is ionic, not molecular (there are no molecules containing one sodium and one chlorine, just a crystal lattice of sodium and chloride ions). But few would hesitate to call NaCl a compound.

[insane_alien]

molecules have no trouble being ionic. the fact that there is an immense amount of intermolecular bonding making up a lattice is also par for the course.

 

on thing you notice about chemistry is that there is always an exception to a definition, even this one.

[nitroglycol]

That's not what it says here:

This definition has evolved as knowledge of the structure of molecules has increased. Earlier definitions were less precise defining molecules as the smallest particles of pure chemical substances that still retain their composition and chemical properties.[3] This definition often breaks down since many substances in ordinary experience, such as rocks, salts, and metals, are composed of atoms or ions, but are not made of molecules.

Emphasis mine. I realize Wikipedia is not the last word, but this is consistent with what I've read elsewhere.

 

Now, there is a situation where the term "molecule" is used in a looser sense, according to the same article:

In the kinetic theory of gases the term molecule is often used for any gaseous particle regardless of their composition.[4] According to this definition noble gases would also be considered molecules despite the fact that they are composed of a single non-bonded atom.

However, this has little relevance to the topic at hand.

[insane_alien]

There is also a disparity between the definitions and common usage. If you asked most chemists what was in a salt molecule they would go 'sodium and chlorine' but if they were writing a paper on it they would likely reffer to salt crystals as sodium chloride lattices.

 

and anyway, lattices can be molecules also. look at diamonds.

[nitroglycol]

and anyway, lattices can be molecules also. look at diamonds.

Not the same kind of lattice as sodium chloride, though. Salt crystals are ionic; diamonds (and graphite, for that matter) are covalent, so they could be viewed as giant molecules, though the article I linked seems to be less than keen on describing them as such:

No typical molecule can be defined for ionic (salts) and covalent crystals (network solids) which are composed of repeating unit cells that extend either in a plane (such as in graphite) or three-dimensionally (such as in diamond or sodium chloride).