Cadmium iodide

Cadmium iodide  Cadmium iodide

Cadmium iodide
Names
IUPAC name

Cadmium(II) iodide

Other names

Cadmium diiodide

Identifiers

CAS Number

* 7790-80-9 Y

3D model (JSmol)

* Interactive image

ChemSpider |

* 23037 Y

ECHA InfoCard | 100.029.294
EC Number |

* 232-223-6

PubChem CID

* 277692

UNII |

* 2F2UPU4KCW Y

CompTox Dashboard (EPA)

* DTXSID20894887

InChI

* InChI=1S/Cd.2HI/h;2*1H/q+2;;/p-2 Y

Key: OKIIEJOIXGHUKX-UHFFFAOYSA-L Y

* InChI=1/Cd.2HI/h;2*1H/q+2;;/p-2

Key: OKIIEJOIXGHUKX-NUQVWONBAZ

SMILES

* [Cd+2].[I-].[I-]

Properties

Chemical formula

| CdI2
Molar mass | 366.22 g/mol
Appearance  | white to pale yellow crystals
Density | 5.640 g/cm3, solid
Melting point | 387 °C (729 °F; 660 K)
Boiling point | 742 °C (1,368 °F; 1,015 K)

Solubility in water

| 787 g/L (0 °C)
847 g/L (20 °C)
1250 g/L (100 °C)
Solubility | soluble in ethanol, acetone, ether and ammonia

Magnetic susceptibility (χ)

| −117.2·10−6 cm3/mol
Structure

Crystal structure

| Trigonal, hP3, space group P3m1, No. 164

Coordination geometry

| octahedral
Hazards
GHS labelling:

Pictograms

Signal word

| Danger

Hazard statements

| H301, H331, H351, H373, H410

Precautionary statements

| P260, P280, P301+P330+P331, P304+P340, P310, P311, P403+P233
NFPA 704 (fire diamond)  |

NIOSH (US health exposure limits):

PEL (Permissible)

| [1910.1027] TWA 0.005 mg/m3 (as Cd)[1]

REL (Recommended)

| Ca[1]

IDLH (Immediate danger)

| Ca [9 mg/m3 (as Cd)][1]
Related compounds

Other anions

| cadmium fluoride
cadmium chloride
cadmium bromide

Other cations

| zinc iodide
mercury(II) iodide

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Y verify (what is YN ?)

Infobox references

Chemical compound

Cadmium iodide is an inorganic compound with the formula CdI2. It is a white hygroscopic solid. It also can be obtained as a mono- and tetrahydrate.[2] It has few applications. It is notable for its crystal structure, which is typical for compounds of the form MX2 with strong polarization effects.

## Preparation

[edit]

Cadmium iodide is prepared by the addition of cadmium metal, or its oxide, hydroxide or carbonate to hydroiodic acid. Also, the compound can be made by heating cadmium with iodine.[2]

## Applications

[edit]

Historically, cadmium iodide was used as a catalyst for the Henkel process, a high-temperature isomerisation of dipotassium phthalate to yield the terephthalate. The salt was then treated with acetic acid to yield potassium acetate and commercially valuable terephthalic acid.[3]

While uneconomical compared to the production of terephthalic acid from p-xylene, the Henkel method has been proposed as a potential route to produce terephthalic acid from furfural. As existing Bio-PET is still reliant on petroleum as a source of p-xylene, the Henkel process could theoretically offer a completely bioplastic route to polyethylene terephthalate.[4]

## Crystal structure

[edit]

The iodide anions in CdI2 form a hexagonal close-packed lattice, while the cadmium cations occupy all of the octahedral holes in alternating layers.

In cadmium iodide the iodide anions form a hexagonal closely packed arrangement while the cadmium cations fill all of the octahedral sites in alternate layers. The resultant structure consists of a layered lattice. This same basic structure is found in many other salts and minerals. Cadmium iodide is mostly ionically bonded but with partial covalent character.[5]

Cadmium iodide's crystal structure is the prototype on which the crystal structures of many other compounds can be considered to be based. Compounds with any of the following characteristics tend to adopt the CdI2 structure:[citation needed]

* Iodides of moderately polarising cations; bromides and chlorides of strongly polarising cations
* Hydroxides of dications, i.e. compounds with the general formula M(OH)2
* Sulfides, selenides and tellurides (chalcogenides) of tetracations, i.e. compounds with the general formula MX2, where X = S, Se, Te

## References

[edit]

1. ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0087". National Institute for Occupational Safety and Health (NIOSH).
2. ^ a b F. Wagenknecht; R. Juza (1963). "Cadmium iodide". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2\. NY, NY: Academic Press. p. 1096.
3. ^ Solomon, I.; Eisenberg, W. (1976). Utilization of coal conversion process by-products. Quarterly report, December 27, 1975--March 27, 1976 (Report). doi:10.2172/7186862.
4. ^ Tachibana, Yuya; Kimura, Saori; Kasuya, Ken-Ichi (2015). "Synthesis and Verification of Biobased Terephthalic Acid from Furfural". Scientific Reports. 5: 8249. Bibcode:2015NatSR...5E8249T. doi:10.1038/srep08249. PMC 4316194. PMID 25648201.
5. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 1211–1212\. ISBN 978-0-08-037941-8.

* v
* t
* e

Cadmium compounds

Cadmium(I)|

* Cd2(AlCl4)2

Cadmium(II)|

* Cd(BF4)2
* CdF2
* CdCl2
* CdBr2
* CdI2
* Cd(CN)2
* CdH2
* CdO
* CdS
* CdSe
* CdTe
* Cd(OH)2
* Cd3N2
* Cd(NO3)2
* CdSO4
* CdSeO4
* CdCrO4
* CdWO4
* CdTeO3
* Cd(C3H5O3)2
* Cd3As2
* Cd3P2
* Cd3(PO4)2
* CsCdCl3
* CsCdBr3
* Cd(CH3CO2)2
* Cd(O2CC17H35)2

* v
* t
* e

Salts and covalent derivatives of the iodide ion

| HI
+H |  |  |  | He

|
|
|
|

LiI | BeI2 | BI3
+BO3 | CI4
+C | NI3
NH4I
+N | I2O4
I2O5
I2O6
I4O9 | IF
IF3
IF5
IF7 | Ne
NaI | MgI2 | AlI
AlI3 | SiI4 | PI3
P2I4

PI5 | S2I2 | ICl
ICl3 | Ar
KI | CaI2 |  | ScI3 | TiI2
TiI3
TiI4 | VI2
VI3 | CrI2
CrI3
CrI4 | MnI2 | FeI2
FeI3 | CoI2 | NiI2
-Ni | CuI | ZnI2 | GaI
GaI3 | GeI2
GeI4
+Ge | AsI3
As2I4
+As | Se  | IBr
IBr3 | Kr
RbI
RbI3 | SrI2 |  | YI3 | ZrI2
ZrI3
ZrI4 | NbI4
NbI5 | MoI2
MoI3 | TcI3 | RuI3 | RhI3 | PdI2 | AgI | CdI2 | InI
InI3 | SnI2
SnI4 | SbI3
+Sb | TeI4
+Te | I−

3 | Xe
CsI
CsI3 | BaI2 |  | LuI3 | HfI3
HfI4 | TaI4
TaI5 | WI2
WI3
WI4 | ReI3
ReI
4 | OsI
OsI2
OsI3 | IrI3
IrI
4 | PtI2
PtI4 | AuI
AuI3 | Hg2I2
HgI2 | TlI
TlI3 | PbI2 | BiI3 | PoI2
PoI4 | AtI | Rn
Fr  | RaI2 |  | Lr  | Rf  | Db  | Sg  | Bh  | Hs  | Mt  | Ds  | Rg  | Cn  | Nh  | Fl  | Mc  | Lv  | Ts  | Og
| ↓  |  |
| LaI2
LaI3 | CeI2
CeI3 | PrI2
PrI3 | NdI2
NdI3 | PmI3 | SmI2
SmI3 | EuI2
EuI3 | GdI2
GdI3 | TbI3 | DyI2
DyI
3 | HoI3 | ErI3 | TmI2
TmI3 | YbI2
YbI3
AcI3 | ThI2
ThI3
ThI4 | PaI4
PaI5 | UI3
UI4 | NpI3 | PuI3 | AmI2
AmI3 | CmI3 | BkI
3 | CfI

CfI
3 | EsI2
EsI3 | Fm  | Md  | No
*[CID]: Compound ID
*[EPA]: U.S. Environmental Protection Agency
*[H301]: H301: Toxic if swallowed
*[H331]: H331: Toxic if inhaled
*[H351]: H351: Suspected of causing cancer
*[H373]: H373: May cause damage to organs through prolonged or repeated exposure
*[H410]: H410: Very toxic to aquatic life with long lasting effects
*[P260]: P260: Do not breathe dust/fume/gas/mist/vapours/spray.
*[P280]: P280: Wear protective gloves/protective clothing/eye protection/face protection.
*[P301+P330+P331]: P301+P330+P331: IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
*[P304+P340]: P304+P340: IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing.
*[P310]: P310: Immediately call a POISON CENTER or doctor/physician.
*[P311]: P311: Call a POISON CENTER or doctor/physician.
*[P403+P233]: P403+P233: Store in a well ventilated place. Keep container tightly closed.
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