new chemist :)

[Chiral atom]

Hi to every body ...

I wish you to accept me in your fourm

and I wish you to excuss me Im not good in english

but Im trying to be better ...

bye bye ..

oh , I forgot to tell you that chemistry is my life

good bye

[Tormod]

Hi there - you are very welcome here. We don't care how good or bad your English is, as long as you don't mind us asking if we don't understand something.

Tim is our chemistry moderator and I'm sure he'll be happy to have another chemistry person around.

[Tim_Lou]

You are aboslutely welcome to our forum... English isnt a problem.
This is a chemistry category, not an English one, right?
(my English is terrible as well)

[Turtle]

Hi! I have to admit that chemistry is a rather weak subject with me. But I love it nonetheless. I'm curious if your log name referes to chiraldry(sp) the quality of handedness?

[FREYA021]

chiral atom is the one that has all R diferent. example, CR4 is chiral if R1,R2,R3,R4 r diferent. those atoms can be opticaly active... u must heard of D or L sugars... it has to do with chirality...

[TeleMad]

Originally Posted by FREYA021

chiral atom is the one that has all R diferent. example, CR4 is chiral if R1,R2,R3,R4 r diferent. those atoms can be opticaly active... u must heard of D or L sugars... it has to do with chirality...

An atom can be a chiral center if it has 4 different atoms/groups attached, such as an asymetrical carbon atom, but it is the molecule that would be chiral.

[OpenMind5]

Argh! Chemistry...I hated that class. It was fun...maybe if i actually paid attention in that class..o well
Welcome never the less. My name is Open Mind 5 and i will be about this site, if u need naything just call, and as everyone said, english is not a problem...i am sure their are brains here that can understand u!

Op5

-Prepare your mind to be opened!
Hu-HA-

[FREYA021]

Originally Posted by TeleMad

An atom can be a chiral center if it has 4 different atoms/groups attached, such as an asymetrical carbon atom, but it is the molecule that would be chiral.

u r right. i just didnt wanna to bother with chem-dictionary... by the way new chemist calls himself chiralAtom
for me u r shinny big A of organic chemistry, stereochemistry well done !

[UncleAl]

Originally Posted by FREYA021

chiral atom is the one that has all R diferent. example, CR4 is chiral if R1,R2,R3,R4 r diferent. those atoms can be opticaly active... u must heard of D or L sugars... it has to do with chirality...

That is sloppy at best and plain wrong at worst. An isolated chiral tetrahedral carbon atom can certainly have four different groups. It can also have four rigorously identical groups, be undistorted, and still be chiral if it has point group T (not T_d or T_h) symmetry. An example is the central carbon in [6.6]chiralane,

http://www.mazepath.com/uncleal/chiral2.gif
http://www.mazepath.com/uncleal/chiral3.gif

Where is the "chiral atom" in a helicene? In a binaphthyl? In a trans-cycloalkene?

Chirality is defined by symmetry - absence of an inversion point, mirror planes, and higher S_n axes of symmetry - not by substitution.

All isolated atoms are intrinsically homochiral via the Weak Interaction and neutral current (Z_0 exchange, nucleus to orbiting electrons). The effect is very weak even in the heaviest elements even with interaction strength scaling as (atomic weight)^4.

Mendeleev Commun. 13(3) 129 (2003)
http://socrates.berkeley.edu/~budker/PubList.html
Phys. Rev. Lett. 82(12) 2484 (1999)
Phys. Rev. Lett. 80(17) 3719 (1998)
Rep. Prog. Phys. 60(11) 1351 (1997)
Phys. Rev. A 52(3) 1895 (1995)
Am. J. Phys. 56 1086 (1988)
http://arXiv.org/abs/cond-mat/0207627

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf

[Fishteacher73]

Ahhh...the wonders of stereochemistry...

While the mechanics of stereo chemistry were way too fun in organic (I think I would rather have pins shoved under my nails than have to go to another organic lab and watch something reflux in a fractional distilation tube for an hour or so again) the implications of it in the biological realm are quite fascinating. The abiolity of our body to only produce certain molecules with a specific chirality is amazing (We can barely do it iunder some circumstances in the lab). Along with that is the chiral specific interactions in the body. Coooll....