PPCHTeX and (non)standard bond angles

[Mojca Miklavec <mojca.miklavec1@email.si>]

Perhaps there is some other better place to post this question, but 
since "ConTeXt" has put quite some effort to be compatible with it and 
since I cannot subscribe to ntg-ppchtex: I've tried to draw some 
chemical formulas with PPCTeX and wasn't able to find any option, 
allowing to visualize sp2 hibridisation on ONE atoms (i.e. 120 degrees). 
It is possible to make some "approximation" (2,4,7 for example), but it 
looks far away from perfect - the angles should be EXACTLY 120 degrees 
in that case (the same goes for NEWMAN).
(some other, but maybe more exotic problems include PH_3, NH_3 for 
example, not forgetting about water)

  H
/
P-H
\
  H

- Does there exist anything that would make SB and other bonds in ONE 
extent to the center of atom (the centar atom needs not be specified if 
it is C atom); perhaps R? How may I draw '/\/\/' for heksane (with angle 
109 degrees)?

- How can I name only one atom in the ring? (with the other places being 
filled with lines)

Thank you,
     Mojca Miklavec