To amplify what Bill mentioned:
It seems that "silica," "silicon," and "silicone" are chronically confused.
One hears the confusion all the time, and most annoyingly from sources (like
the media) that should be doing their best to prevent such confusion.
Silicon is an element. Symbol "Si" and one of the most abundant elements on
the planet (might be the most abundant). Very pure silicon crystals are
grown and doped to produce semiconductors. This is why the valley in
California is the SILICON Valley (where semiconductors are made, near San
Francisco) not the SILICONE valley (sometimes known as "cleavage", and
usually nearer to Hollywood <g>).
Silica is a specific compound, SiO2 (silicon dioxide) and commonly found as
quartz, silica glass (used in fiber optics for example), opal and loads of
other things.
Silicone is also a compound, usually polymerized. Otherwise known as
polydimethylsiloxane. Two methyl groups (CH3) bound to a "siloxane" group
(SiO) and all strung together as a polymer. Length, cross-linkage and the
like form different viscosities (a HUGE range) and properties. Silicone is
generally chemically inert, non-flammable and mostly benign. Used in cooling
and lubricating applications as a liquid, in breast implants as a gel and in
many, many other medical implants as a solid.
Ok, so I was feeling pedantic this morning... I'll just go pick up some film
and visit a client now.
---
Scott Gomez
-----Original Message-----
From: Bill Pearce [mailto:bspearce@xxxxxxxxxxxxx]
Subject: [OM] [OT]silica/silicone
I'm not a metallurgist, I don't even play one on television, but here goes
anyway. This will be broadly general, and generally broad, so if anyone
knows more accurate details, jump in.
Silica and silicone are frequently used interchangably, but are really quite
different. Silicone is a complex chemical, frequently used as a lubricant.
Silica is the main ingredient of sand.
<snip>
Bill Pearce
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|