Substituent angular spacing

The essence of a chain is that its atoms share a constant (fixed) angular spacing (Figure 28). This angle is typically 120° (i.e., trigonal), but the user may prefer a different value (Figure 30). For example, 150° emphasizes the coherence of the chain, whereas 105° provides more room for substituents. 

This algorithm returns the optimal angular spacing between the remaining unplaced substituents of the seed atom. 

If the seed atom is a core chain atom (not a capping substituent). Algorithm 9 is applied. The only subtlety is in choosing, for the angular spacing. 

Invoke Algorithms 6 and 7 to get the substituent sequence and residual angular spacing. 

The ring system represents a more or less fiat board with a space-demanding angular substituent in the 3-position. 

---