Calcium iodide

Crystal structure
	__ Ca 2+ __ I -
General
Surname	Calcium iodide
other names	Calcium (II) iodide; Calcium diiodide;
Ratio formula	CaI 2
Brief description	white to yellowish solid
External identifiers / databases
EC number	233-276-8
ECHA InfoCard	100.030.238
PubChem	5462722
ChemSpider	59629
Wikidata	Q412538
properties
Molar mass	293.89 g mol −1
Physical state	firmly
density	3.956 g cm −3 (20 ° C)
Melting point	740 ° C
boiling point	1100 ° C
solubility	easily soluble in water
safety instructions
GHS labeling of hazardous substances Caution
H and P phrases	H: 315-319
	P: 302 + 352
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Calcium iodide is a chemical compound of calcium and is one of the iodides . It is a white solid that slowly turns yellow in air.

history

By reducing calcium iodide with sodium , Henri Moissan succeeded for the first time in obtaining pure calcium.

Extraction and presentation

Calcium iodides containing water crystallize out of aqueous solutions when concentrated. Depending on the concentration, the hexa- or tetrahydrate is formed. Anhydrous calcium iodide cannot be obtained by dehydrating the hydrate; instead it can be prepared from a calcium hydroxide solution and iodine . Calcium iodide and calcium iodate are formed , which is then reduced.

{\ displaystyle \ mathrm {6 \ Ca (OH) _ {2} +6 \ I_ {2} \ longrightarrow 5 \ CaI_ {2} + Ca (IO_ {3}) _ {2} +5 \ H_ {2} O}}

Another possible way to prepare anhydrous calcium iodide is the decomposition of calcium oxalate with iodine.

{\ displaystyle \ mathrm {CaC_ {2} O_ {4} + I_ {2} \ longrightarrow CaI_ {2} + 2CO_ {2} \ uparrow}}

properties

The properties of anhydrous and water-containing calcium iodide differ significantly. The various hydrates are easily dissolving, crystalline masses that melt at 42 ° C, i.e. they dissolve in their own crystal water. If calcium iodide hydrate comes into contact with air or light, it can absorb carbon dioxide or release iodine and, as a result, turns yellow.

The anhydrous calcium iodide, on the other hand, is a high-melting crystalline solid that crystallizes in a typical layer structure , the hexagonal cadmium iodide structure. In the gaseous state it forms linear molecules.

use

Calcium iodide, like potassium iodide, is an expectorant .

In technology, the compound is used as a scintillation crystal and in halogen lamps .

Individual evidence

↑ Calcium diiodide at webelements.com .
↑ ^a ^b ^c ^d ^e ^f data sheet Calcium iodide, ultra dry, 99.999% (metals basis) from AlfaAesar, accessed on December 7, 2019 ( PDF )(JavaScript required) .
↑ Alain Tressaud: Henri Moissan: Nobel Prize for Chemistry in 1906. In: Angewandte Chemie . 2006, 118, pp. 6946-6950, doi : 10.1002 / anie.200601600 .
^ ^A ^b Beate Blümer-Schwinum, Hermann Hager, Franz von Bruchhausen, E. Nuremberg, Peter Surman: Hagers Handbook of Pharmaceutical Practice, Volumes 1-4 . 5th edition, Birkhäuser, 1995, ISBN 978-3-540-52688-9 , p. 607.
↑ ^a ^b entry on calcium iodide. In: Römpp Online . Georg Thieme Verlag, accessed on July 15, 2014.
^ AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 1241.
↑ Kenneth L. Becker, John P. Bilezikian: Principles and practice of endocrinology and metabolism. 3rd edition, Lippincott Williams & Wilkins, 2001, ISBN 978-0-781-71750-2 , p. 362.

[webelements-1] Calcium diiodide at webelements.com .

[alfa-2] ↑ ^a ^b ^c ^d ^e ^f data sheet Calcium iodide, ultra dry, 99.999% (metals basis) from AlfaAesar, accessed on December 7, 2019 ( PDF )(JavaScript required) .

[3] Alain Tressaud: Henri Moissan: Nobel Prize for Chemistry in 1906. In: Angewandte Chemie . 2006, 118, pp. 6946-6950, doi : 10.1002 / anie.200601600 .

[Hager-4] A ^b Beate Blümer-Schwinum, Hermann Hager, Franz von Bruchhausen, E. Nuremberg, Peter Surman: Hagers Handbook of Pharmaceutical Practice, Volumes 1-4 . 5th edition, Birkhäuser, 1995, ISBN 978-3-540-52688-9 , p. 607.

[römpp-5] try on calcium iodide. In: Römpp Online . Georg Thieme Verlag, accessed on July 15, 2014.

[6] AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 1241.

[7] Kenneth L. Becker, John P. Bilezikian: Principles and practice of endocrinology and metabolism. 3rd edition, Lippincott Williams & Wilkins, 2001, ISBN 978-0-781-71750-2 , p. 362.