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From: Edward Green on 21 Dec 2008 14:27
On Dec 20, 3:32 am, Andrew Usher <k_over_hb...(a)yahoo.com> wrote:
> It came to me one day when observing paraffin wax freeze, that the wax
> could not be a perfect crystal since it is not a pure substance.
> Rather, it consists of countless isomers; yet, it seems to be
> crystalline from its opacity

Don't follow your reasoning. Many crystals are clear. Do organics
tend to become opaque on crystalization as opposed to remaining clear
on glassification?

> and apparent sharp melting and freezing.

I can easily wave my hands around that. Mixture of random length
(longish) carbon chains have a statistically sharp pseudo-
crytalization of domains of matching chain fragments.

Because I said so.

> Natural fats and waxes must be the same as paraffin in this regard, as
> their physical properties are exactly analogous.
>
> I drew, therefore, an immediate parallel with crystalline plastics,
> which seem very similar (though having a much higher tensile
> strength). Am I correct in doing so? I have never read anything about
> the solid structure of fats and waxes but I do not think I can be
> wrong here.
>
> So we have a group of materials that can not form perfect crystals (or
> segregate into solids that do), which are all organic, but there can
> be made inorganic polymers that surely behave the same way. They are,
> of course, thermodynamically unstable, as all organics are.

Again don't follow your reasoning. What do you mean "all organics
are" ... "thermodynamically unstable"? Do you mean they all are
unstable wrt some other atmoic (i.e., chemcially different)
arrangement of the the carbons and hetero-atoms? Or do you mean that,
as pseudo-crystals, they are thermodynamically unstable against an
eventual segregation into crystals of similar species? But why would
organics be special in this regard (assuming it is true)?

> So can I set down a general rule, that the thermodynamically most
> stable state of any aggregation of elements, will form one or more
> crystalline phases, which form the whole bulk, at sufficiently low
> temperatures?

I doubt solid wax is more than partially ordered. Whether, assuming
no chemical changes (fixed spectrum of chains lengths) this is
unstable wrt segregation, I don't know.
From: Edward Green on 21 Dec 2008 14:32
On Dec 21, 12:45 am, RLW <rlwatk...(a)gmail.com> wrote:

<...>

> I did think I should
> give you my best shot at an answer, better at least than my earlier post
> giving Uncle Al his daily ration of grief.

He thrives on it.
From: Mark Thorson on 21 Dec 2008 16:35
Andrew Usher wrote:
>
> On Dec 20, 6:58 pm, Mark Thorson <nos...(a)sonic.net> wrote:
> > Salmon Egg wrote:
> >
> > > This is certainly not my field of expertise. My question is: What is the
> > > x-ray diffraction pattern of solidified wax? Is there any evidence of
> > > microcrystals?
> >
> > If you break a piece of wax (or paraffin masquerading as wax),
> > you'll see a fine polycrystalline fracture surface. More pronounced
> > with paraffin (US usage, not UK) than with natural waxes (beeswax).
>
> I know that wax is not amorphous, but how can it be entirely
> crystalline? That was my question.

It's not a perfect crystal. Most crystals aren't.
But the long hydrocarbon chains will line up with
each other, forming imperfect crystals.

Consider a plate of spaghetti. Will there be
places where the strands of spaghetti line up
parallel to each other? There certainly will be.
They won't form a perfect "spaghetti crystal",
but there will be regions where most of the
strands are aligned.

> > Some additives such as stearic acid are often used as hardeners
> > for paraffin wax. Pure stearic acid solidifies into a large-grain
> > polycrystalline solid.
>
> So it wouldn't be so without additives?

No, I confused you by giving you too much information.
Pure paraffin is crystalline, but with finer grain
than stearic acid.
From: Edward Green on 21 Dec 2008 22:47
On Dec 21, 4:35 pm, Mark Thorson <nos...(a)sonic.net> wrote:
> Andrew Usher wrote:
<...>
> > I know that wax is not amorphous, but how can it be entirely
> > crystalline? That was my question.
>
> It's not a perfect crystal.  Most crystals aren't.
> But the long hydrocarbon chains will line up with
> each other, forming imperfect crystals.
>
> Consider a plate of spaghetti.  Will there be
> places where the strands of spaghetti line up
> parallel to each other?  There certainly will be.
> They won't form a perfect "spaghetti crystal",
> but there will be regions where most of the
> strands are aligned.

That's what I says, and what's more, I says it first.

Of course, both of us may be full of it.

> > > Some additives such as stearic acid are often used as hardeners
> > > for paraffin wax.  Pure stearic acid solidifies into a large-grain
> > > polycrystalline solid.
>
> > So it wouldn't be so without additives?
>
> No, I confused you by giving you too much information.
> Pure paraffin is crystalline, but with finer grain
> than stearic acid.

From: Lofty Goat on 21 Dec 2008 23:08
On Sat, 20 Dec 2008 16:09:18 -0800, Mark Thorson wrote:

> RLW wrote:
>>
>> On Sat, 20 Dec 2008 10:38:49 -0800, Uncle Al wrote:
>> > No, stupid. Glycerol triesters. . . .
>>
>> Gee Al, the IUC is not going to penalize you if you just call them
>> "triglycerides", like everyone else does.
>
> Ever since the chiralane nomenclature controversy, Uncle Al writes the
> rules. :-)

Hell, someone ought to. Over time, Usenet has morphed from the world's
largest university coffee-shop into Dodge City at high noon.
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