At present, there is an undocumented requirement on the contents of CONNECT records, namely that one of them MUST contain the (dummy) links "-" and "+" !

For example, to draw pentafluorobenzylalcohol correctly, i.e. without a bond between hydrogens H1 and H2, you must use the following connectivity information:

 PFB
 ATOM   O1 C7 C1 C2 C3 C4 C5 C6 F2 F3 F4 F5 F6 H1 H2 H3
 CONNECT - O1 C7 C1 C2 C3 C4 C5 C6 C1 +
 CONNECT C2 F2
 CONNECT C3 F3
 CONNECT C4 F4
 CONNECT C5 F5
 CONNECT C6 F6
 CONNECT C7 H1
 CONNECT C7 H2
 CONNECT O1 H3