Beryllium iodide

Beryllium iodide
Names

Systematic IUPAC name Beryllium iodide
Identifiers
CAS Number	7787-53-3^N
3D model (Jmol)	Interactive image
ChemSpider	74209^Y
ECHA InfoCard	100.029.199
PubChem	82231
InChI InChI=1S/Be.2HI/h;21H/q+2;;/p-2^Y Key: JUCWKFHIHJQTFR-UHFFFAOYSA-L^Y InChI=1/Be.2HI/h;21H/q+2;;/p-2 Key: JUCWKFHIHJQTFR-NUQVWONBAT
SMILES [Be+2].[I-].[I-]
Properties
Chemical formula	Be I₂
Molar mass	262.821 g/mol
Appearance	colorless needle-like crystals
Density	4.325 g/cm³
Melting point	480 °C (896 °F; 753 K)
Boiling point	590 °C (1,094 °F; 863 K)
Solubility in water	reacts explosively
Solubility	Slightly soluble in CS₂ Soluble in ethanol, diethyl ether
Structure
Crystal structure	orthorhombic
Thermochemistry
Specific heat capacity (C)	71.14 J/(mol × K)
Std molar entropy (S^o₂₉₈)	130 J/mol K
Std enthalpy of formation (Δ_fH^o₂₉₈)	-192.62 kJ/mol
Gibbs free energy (Δ_fG˚)	-210 kJ/mol
Std enthalpy of combustion (Δ_cH^o₂₉₈)	19 kJ/mol
Hazards
Main hazards	see Berylliosis
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 0.002 mg/m³ C 0.005 mg/m³ (30 minutes), with a maximum peak of 0.025 mg/m³ (as Be)
REL (Recommended)	Ca C 0.0005 mg/m³ (as Be)
IDLH (Immediate danger)	Ca [4 mg/m³ (as Be)]
Related compounds
Other anions	Beryllium fluoride Beryllium chloride Beryllium bromide
Other cations	magnesium iodide calcium iodide strontium iodide barium iodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N (what is ^YN ?)
Infobox references

Beryllium iodide is the chemical compound with the formula BeI₂. It is very hygroscopic and reacts violently with water, forming hydroiodic acid.

Beryllium iodide can be prepared by reacting beryllium metal with elemental iodine at temperatures of 500 °C to 700 °C:

Beryllium iodide is also formed when beryllium carbide reacts with hydrogen iodide in the gas phase:

The iodine in beryllium iodide is easily replaced with the other halogens; it reacts with fluorine giving beryllium fluoride and fluorides of iodine, with chlorine giving beryllium chloride, and with bromine giving beryllium bromide. Beryllium iodide also reacts violently with oxidising agents such as chlorate and permanganate to give purple vapour of iodine. The solid and vapor are both flammable in air.

Beryllium iodide can be used in the preparation of high-purity beryllium by the decomposition of the compound on a hot tungsten filament.