Coordination geometry
Coordination number Geometry Examples of discrete ( finite ) complex Examples in crystals ( infinite solids )
2 linear Ag ( CN ) 2 in KAg ( CN ) 2 Ag in silver cyanide , Au in AuI
3 trigonal planar HgI 3 O in TiO 2 rutile structure
4 tetrahedral CoCl 4 Zn and S in zinc sulfide , Si in silicon dioxide
4 square planar AgF 4 CuO
5 trigonal bipyramidal SnCl 5
5 square pyramidal InCl 5 in ( NEt 4 ) 2 InCl 5
6 octahedral Fe ( H 2 O ) 6 Na and Cl in NaCl
6 trigonal prismatic W ( CH 3 ) 6 As in NiAs , Mo in MoS 2
7 pentagonal bipyramidal ZrF 7 in ( NH 4 ) 3 ZrF 7 Pa in PaCl 5
7 capped octahedral MoF 7 La in A-La 2 O 3
7 capped trigonal prismatic TaF 7 in K 2 TaF 7
8 square antiprismatic TaF 8 in Na 3 TaF 8 Zr ( H 2 O ) 8 aqua complex Thorium ( IV ) iodide
8 dodecahedral ( note : whilst this is the term generally used , the correct term is bisdisphenoid or snub disphenoid as this polyhedron is a deltahedron ) Mo ( CN ) 8 in K 4 [ Mo ( CN ) 8 ] .2H 2 O Zr in K 2 ZrF 6
8 bicapped trigonal prismatic ZrF 8 PuBr 3
8 cubic Caesium chloride , calcium fluoride
8 hexagonal bipyramidal N in Li 3 N
8 octahedral , trans-bicapped Ni in nickel arsenide , NiAs ; 6 As neighbours + 2 Ni capping
8 trigonal prismatic , triangular face bicapped Ca in CaFe 2 O 4
9 tricapped trigonal prismatic [ ReH 9 ] in potassium nonahydridorhenate Th ( H 2 O ) 9 aqua complex SrCl 2 .6H 2 O , Th in RbTh 3 F 13
9 capped square antiprismatic [ Th ( tropolonate ) 4 ( H 2 O ) ] La in LaTe 2
Table of coordination geometries
A table of the coordination geometries encountered is shown below with examples of their occurrence in complexes found as discrete units in compounds and coordination spheres around atoms in crystals ( where there is no discrete complex ) .
The term coordination geometry is used in a number of related fields of chemistry and solid state chemistry/physics.