MINERALS AND SYNTHETIC COMPOUNDS, AmXn, IN WHICH X ATOMS ARE
          CLOSE PACKED AND A ATOMS OCCUPY OCTAHEDRAL INTERSTICES
 
.

CdI2

                  click here to see a key to this data bar                                  

octa

50%

hcp

layer

6 edges

A- 6c, X- 3c/hcp

.

  structure

.
. .
     CdI2 has a layer structure with A atoms occupying 100% of the octahedral voids of .
every other layer for an overall occupancy rate of 50%.  The structure is analogous to .
the CdCl2 layer structure shown previously except that the layers stack HCP not FCC.
  .
Ex. CdI2  (cadmium iodide)    ( Cd - A , I - X ) .
.
Crystal lattice
     The HCP layering arrangement of the structure is demonstrated by the lattice
model.
.      
 

CdI2

 
    Figure 85 -  CdI2 lattice structure

click image to enlarge

                        
   
 
.      
Polyhedral framework
     Same as for CdCl2 except that the layers are positioned in the HCP formation.
.      

linking surfaces

Cleavage

 

     (100) - perfect
                
Crystal habit             

6 edges

     tabular
.      
Isostructural minerals/compounds
Ag2F, CaI2, CdI2, CoBr2, CoI2, CoTe2, FeBr2, FeI2, GeI2, HfS2, HfSe2, IrTe2, MgBr2,
MgI2, MnBr2, MnI2, NiTe2, PdI2, PdTe2, PtS2, PtSe2, PtTe2, SiTe2, SnS2, SnSe2,
a-TaS2, TiBr2, TiCl2, TiI2, TiSe2, TiTe2, VBr2, VCl2, VI2, W2C, ZrS2, ZrSe2, ZrTe2,
Ca(OH)2, Mn(OH)2, Mg(OH)2, Zn(OH)2, Mg4NiO(OH)9
.

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