CAIE A-Level Chemistry 28.2.2 Ligands and Coordinate Bonding
Practise defining ligands and identifying the donor atom and lone pair that form a dative bond to a metal ion.
- Syllabus
- 2028–2030
- Course
- Chemistry 9701
- Level
- A2
Practise defining ligands and identifying the donor atom and lone pair that form a dative bond to a metal ion.
Ruthenium and osmium are transition metals below iron in Group 8 of the Periodic Table.
Fig. 4.1 shows another ruthenium complex.

Fig. 4.1
This complex contains the neutral ligand pyrazine.

Suggest how pyrazine is able to bond to two separate ruthenium ions.
(pyrazine has) a lone pair on each N (atoms) / two lone pairs (on the N's)
AND which can be donated / form a coordinate / dative bond (with Ru)