Heavy Chiral Intermetallics

Uncle Al UncleAl0 at hate.spam.net
Sun Aug 19 21:33:58 EST 2001

Uncle Al needs a little help from x-ray crystallography adepts. 
Uncle Al has a fetish for heavy atom chiral unit cells.  If
anybody has a copy of CRYSTMET or ICSD gathering dust from lack
of use, behold a bit of scholarly recreation:

Table V

Cristal <cristal at cybercable.tm.fr> generously provided 16 chiral
ionic inorganic candidates.  Alas, they were ferroelastic,
twinned (naughty naughty Pb_3_GeO_5_), metastable BiPO_4_)... and
BiTeI ICSD had the wrong structure entirely (J. Solid State Chem.
114 379 (1995) shows space group P3m1 (#156)).  Bummer!

The only remaining possibilities are chiral intermetallics. 
AuBe, AlPt, Al_5_W, CoU, and AlAu_4_ are already in hand.  Can
anybody outdo Uncle Al?

The number of candidates is severely circumscribed by tight

   1. Intermetallics only (*No* organics, organometallics, or
ionic inorganics) 
   2. Unit cell volume less than 350 cubic angstroms.  (We'll go
for a slightly bigger unit cell volume given the size of heavy
metal atoms)
   3. *Must* contain one or more atoms of Ta, W, Pt, Au, Tl, Pb,
or Bi
   4. *Only* space groups P3(1), P3(2), P4(1), P4(3), P6(2),
P6(4), P6(1), P6(5) 
   5. If no hits, then space groups P2, P2(1), C2, I4, I4(1),
P(4), P4(2), P3, R3, P6, P6(3) 
   6. *No* P2(1)3; no SnAu(5) (wrong assignment of space group).

Post 'em if you've got 'em.  E-mail info at the URL above.

Thank you!

(If Trisomy 21 Down Syndrome Mongoloid idiots get lavish 24/7
State-supplied gratis medical care as their right, "ubi est mea?"
for a scholarly inquiry?)

Uncle Al
 (Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?"  The Net!

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