Cadmium iodide

Last updated
Cadmium iodide
Cadmium-iodide-3D-balls.png
Cadmium-iodide-3D-octahedra.png
Cadmium iodide (1).jpg
Names
IUPAC name
Cadmium(II) iodide
Other names
Cadmium diiodide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.029.294 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 232-223-6
PubChem CID
UNII
  • InChI=1S/Cd.2HI/h;2*1H/q+2;;/p-2 Yes check.svgY
    Key: OKIIEJOIXGHUKX-UHFFFAOYSA-L Yes check.svgY
  • InChI=1/Cd.2HI/h;2*1H/q+2;;/p-2
    Key: OKIIEJOIXGHUKX-NUQVWONBAZ
  • [Cd+2].[I-].[I-]
Properties
CdI2
Molar mass 366.22 g/mol
Appearancewhite 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)
787 g/L (0 °C)
847 g/L (20 °C)
1250 g/L (100 °C)
Solubility soluble in ethanol, acetone, ether and ammonia
-117.2·10−6 cm3/mol
Structure
Trigonal, hP3, space group P3m1, No. 164
octahedral
Hazards
GHS labelling:
GHS-pictogram-skull.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
Danger
H301, H331, H351, H373, H410
P260, P280, P301+P330+P331, P304+P340, P310, P311, P403+P233
NFPA 704 (fire diamond)
NFPA 704.svgHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
0
0
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).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Cadmium iodide is the 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.

Contents

Preparation

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

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

The iodide anions in CdI2 form a hexagonal close-packed lattice, while the cadmium cations occupy all of the octahedral holes in alternating layers. Cadmium-iodide-3D-layers.png
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 close 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 many other compounds can be considered to be based. Compounds with any of the following characteristics tend to adopt the CdI2 structure:[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Terephthalic acid</span> Chemical compound

Terephthalic acid is an organic compound with formula C6H4(CO2H)2. This white solid is a commodity chemical, used principally as a precursor to the polyester PET, used to make clothing and plastic bottles. Several million tons are produced annually. The common name is derived from the turpentine-producing tree Pistacia terebinthus and phthalic acid.

<span class="mw-page-title-main">Isophthalic acid</span> Chemical compound

Isophthalic acid is an organic compound with the formula C6H4(CO2H)2. This colorless solid is an isomer of phthalic acid and terephthalic acid. The main industrial uses of purified isophthalic acid (PIA) are for the production of polyethylene terephthalate (PET) resin and for the production of unsaturated polyester resin (UPR) and other types of coating resins.

<span class="mw-page-title-main">Cadmium chloride</span> Chemical compound

Cadmium chloride is a white crystalline compound of cadmium and chloride, with the formula CdCl2. This salt is a hygroscopic solid that is highly soluble in water and slightly soluble in alcohol. The crystal structure of cadmium chloride (described below), is a reference for describing other crystal structures. Also known are CdCl2•H2O and the hemipentahydrate CdCl2•2.5H2O.

<span class="mw-page-title-main">Dimethyl terephthalate</span> Chemical compound

Dimethyl terephthalate (DMT) is an organic compound with the formula C6H4(COOCH3)2. It is the diester formed from terephthalic acid and methanol. It is a white solid that melts to give a distillable colourless liquid.

<span class="mw-page-title-main">Sodium iodide</span> Chemical compound

Sodium iodide (chemical formula NaI) is an ionic compound formed from the chemical reaction of sodium metal and iodine. Under standard conditions, it is a white, water-soluble solid comprising a 1:1 mix of sodium cations (Na+) and iodide anions (I−) in a crystal lattice. It is used mainly as a nutritional supplement and in organic chemistry. It is produced industrially as the salt formed when acidic iodides react with sodium hydroxide. It is a chaotropic salt.

<span class="mw-page-title-main">Cadmium oxide</span> Inorganic compound with the formula CdO

Cadmium oxide is an inorganic compound with the formula CdO. It is one of the main precursors to other cadmium compounds. It crystallizes in a cubic rocksalt lattice like sodium chloride, with octahedral cation and anion centers. It occurs naturally as the rare mineral monteponite. Cadmium oxide can be found as a colorless amorphous powder or as brown or red crystals. Cadmium oxide is an n-type semiconductor with a band gap of 2.18 eV at room temperature.

<span class="mw-page-title-main">Nickel(II) iodide</span> Chemical compound

Nickel(II) iodide is an inorganic compound with the formula NiI2. This paramagnetic black solid dissolves readily in water to give bluish-green solutions, from which crystallizes the aquo complex [Ni(H2O)6]I2 (image above). This bluish-green colour is typical of hydrated nickel(II) compounds. Nickel iodides find some applications in homogeneous catalysis.

<span class="mw-page-title-main">Silver subfluoride</span> Chemical compound

Silver subfluoride is the inorganic compound with the formula Ag2F. This is an unusual example of a compound where the oxidation state of silver is fractional. The compound is produced by the reaction of silver and silver(I) fluoride:

<span class="mw-page-title-main">Cadmium nitrate</span> Chemical compound

Cadmium nitrate describes any of the related members of a family of inorganic compounds with the general formula Cd(NO3)2·xH2O. The most commonly encountered form being the tetrahydrate.The anhydrous form is volatile, but the others are colourless crystalline solids that are deliquescent, tending to absorb enough moisture from the air to form an aqueous solution. Like other cadmium compounds, cadmium nitrate is known to be carcinogenic. According to X-ray crystallography, the tetrahydrate features octahedral Cd2+ centers bound to six oxygen ligands.

<span class="mw-page-title-main">Calcium iodide</span> Chemical compound

Calcium iodide (chemical formula CaI2) is the ionic compound of calcium and iodine. This colourless deliquescent solid is a salt that is highly soluble in water. Its properties are similar to those for related salts, such as calcium chloride. It is used in photography. It is also used in cat food as a source of iodine.

<span class="mw-page-title-main">Beryllium bromide</span> Chemical compound

Beryllium bromide is the chemical compound with the formula BeBr2. It is very hygroscopic and dissolves well in water. The compound is a polymer with tetrahedral coordinated Be centres.

<span class="mw-page-title-main">Beryllium iodide</span> Chemical compound

Beryllium iodide is the inorganic compound with the formula BeI2. It is a hygroscopic white solid.

<span class="mw-page-title-main">Cobalt(II) iodide</span> Chemical compound

Cobalt(II) iodide or cobaltous iodide are the inorganic compounds with the formula CoI2 and the hexahydrate CoI2(H2O)6. These salts are the principal iodides of cobalt.

<span class="mw-page-title-main">Cobalt(II) hydroxide</span> Chemical compound

Cobalt(II) hydroxide or cobaltous hydroxide is the inorganic compound with the formula Co(OH)
2, consisting of divalent cobalt cations Co2+
 and hydroxide anions OH−
. The pure compound, often called the "beta form" is a pink solid insoluble in water.

<span class="mw-page-title-main">Cadmium hydroxide</span> Chemical compound

Cadmium hydroxide is an inorganic compound with the formula Cd(OH)2. It is a white crystalline ionic compound that is a key component of nickel–cadmium battery.

<span class="mw-page-title-main">Germanium(II) iodide</span> Chemical compound

Germanium(II) iodide is an iodide of germanium, with the chemical formula of GeI2.

Iron(II) iodide is an inorganic compound with the chemical formula FeI2. It is used as a catalyst in organic reactions.

<span class="mw-page-title-main">Chromium(II) iodide</span> Chemical compound

Chromium(II) iodide is the inorganic compound with the formula CrI2. It is a red-brown or black solid. The compound is made by thermal decomposition of chromium(III) iodide. Like many metal diiodides, CrI2 adopts the "cadmium iodide structure" motif, i.e., it features sheets of octahedral Cr(II) centers interconnected by bridging iodide ligands. Reflecting the effects of its d4 configuration, chromium's coordination sphere is highly distorted.

<span class="mw-page-title-main">Praseodymium diiodide</span> Chemical compound

Praseodymium diiodide is a chemical compound with the empirical formula of PrI2, consisting of praseodymium and iodine. It is an electride, with the ionic formula of Pr3+(I−)2e−, and therefore not a true praseodymium(II) compound.

<span class="mw-page-title-main">Lanthanum(III) iodide</span> Chemical compound

Lanthanum(III) iodide is an inorganic compound containing lanthanum and iodine with the chemical formula LaI
3.

References

  1. 1 2 3 NIOSH Pocket Guide to Chemical Hazards. "#0087". National Institute for Occupational Safety and Health (NIOSH).
  2. 1 2 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.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.