Mercury(II) iodide

Mercury(II) iodide
	; Mercury(II) iodide (α form)
	; Mercury(II) iodide (β form)
	; β (left) and α (right) forms
Names
	IUPAC name Mercury(II) iodide
	Other names Mercury diiodide; Mercuric iodide; Red mercury (α form only); Coccinite (α form only)
Identifiers
CAS Number	7774-29-0 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:49659 ;
ChemSpider	22893 ;
DrugBank	DB04445 ;
ECHA InfoCard	100.028.976
EC Number	231-873-8;
Gmelin Reference	277788
PubChem CID	24485;
UNII	R03O05RB0P ;
CompTox Dashboard (EPA)	DTXSID9042124 ;
	InChI InChI=1S/Hg.2HI/h;21H/q+2;;/p-2 Key: YFDLHELOZYVNJE-UHFFFAOYSA-L ; InChI=1/Hg.2HI/h;21H/q+2;;/p-2 Key: YFDLHELOZYVNJE-NUQVWONBAE;
	SMILES I[Hg]I;
Properties
Chemical formula	HgI2
Molar mass	454.40 g/mol
Appearance	orange-red powder
Odor	odorless
Density	6.36 g/cm3
Melting point	259 °C (498 °F; 532 K)
Boiling point	350 °C (662 °F; 623 K)
Solubility in water	6 mg/100 mL
Solubility product (Ksp)	2.9×10−29
Solubility	slightly soluble in alcohol, ether, acetone, chloroform, ethyl acetate, CS2, olive oil, castor oil Soluble in excess KI(Potassium iodide) forming soluble complex K2[Hg2I4 ](Potassium tetraiodomercurate(II)) also known as Nessler's reagent
Magnetic susceptibility (χ)	−128.6·10−6 cm3/mol
Refractive index (nD)	2.455
Structure
Crystal structure	Tetrahedral
Pharmacology
ATC code	D08AK30 (WHO)
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H300, H310, H330, H373, H410
Precautionary statements	P260, P262, P264, P270, P271, P273, P280, P284, P301+P310, P302+P350, P304+P340, P310, P314, P320, P321, P322, P330, P361, P363, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)	3 0 0
Flash point	Non-flammable
Related compounds
Other anions	Mercury(II) fluoride; Mercury(II) chloride; Mercury(II) bromide
Other cations	Zinc iodide; Cadmium iodide
Related compounds	Mercury(I) iodide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Mercury(II) iodide is a chemical compound with the molecular formula Hg I₂. It is typically produced synthetically but can also be found in nature as the extremely rare mineral coccinite. Unlike the related mercury(II) chloride it is hardly soluble in water (<100 ppm).

^ John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99 ed.). CRC Press. pp. 5–189. ISBN 978-1138561632.

[crc-1] John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99 ed.). CRC Press. pp. 5–189. ISBN 978-1138561632.

[1]

Names
Mercury(II) iodide (α form)
Mercury(II) iodide (β form)
β (left) and α (right) forms
IUPAC name Mercury(II) iodide
Other names Mercury diiodide Mercuric iodide Red mercury (α form only) Coccinite (α form only)
Identifiers
CAS Number	7774-29-0^Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:49659^Y
ChemSpider	22893^Y
DrugBank	DB04445^Y
ECHA InfoCard	100.028.976
EC Number	231-873-8
Gmelin Reference	277788
PubChem CID	24485
UNII	R03O05RB0P^Y
CompTox Dashboard (EPA)	DTXSID9042124
InChI InChI=1S/Hg.2HI/h;21H/q+2;;/p-2^Y Key: YFDLHELOZYVNJE-UHFFFAOYSA-L^Y InChI=1/Hg.2HI/h;21H/q+2;;/p-2 Key: YFDLHELOZYVNJE-NUQVWONBAE
SMILES I[Hg]I
Properties
Chemical formula	HgI₂
Molar mass	454.40 g/mol
Appearance	orange-red powder
Odor	odorless
Density	6.36 g/cm³
Melting point	259 °C (498 °F; 532 K)
Boiling point	350 °C (662 °F; 623 K)
Solubility in water	6 mg/100 mL
Solubility product (K_sp)	2.9×10⁻²⁹^[1]
Solubility	slightly soluble in alcohol, ether, acetone, chloroform, ethyl acetate, CS₂, olive oil, castor oil Soluble in excess KI(Potassium iodide) forming soluble complex K₂[Hg₂I₄ ](Potassium tetraiodomercurate(II)) also known as Nessler's reagent
Magnetic susceptibility (χ)	−128.6·10⁻⁶ cm³/mol
Refractive index (n_D)	2.455
Structure
Crystal structure	Tetrahedral
Pharmacology
ATC code	D08AK30 (WHO)
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H300, H310, H330, H373, H410
Precautionary statements	P260, P262, P264, P270, P271, P273, P280, P284, P301+P310, P302+P350, P304+P340, P310, P314, P320, P321, P322, P330, P361, P363, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)	3 0 0
Flash point	Non-flammable
Related compounds
Other anions	Mercury(II) fluoride Mercury(II) chloride Mercury(II) bromide
Other cations	Zinc iodide Cadmium iodide
Related compounds	Mercury(I) iodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references