Diiodosilane
[CAS# 13760-02-6]

Identification

• Classification: Chemical reagent >> Silane reagent
• Name: Diiodosilane
• Molecular Formula: H₂I₂Si
• Molecular Weight: 283.91
• CAS Registry Number: 13760-02-6
• EC Number: 626-077-6
• SMILES: [SiH2](I)I

Properties

• Boiling point: 153.7 ºC 760 mmHg (Calc.)^*, 163.2 - 168.4 ºC (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS02;GHS05;GHS07 DangerGHS02
• Hazard Statements: H226-H260-H302-H312-H314-H332
• Precautionary Statements: P210-P223-P231+P232-P233-P240-P241-P242-P243-P260-P261-P264-P270-P271-P280-P301+P317-P301+P330+P331-P302+P335+P334-P302+P352-P302+P361+P354-P303+P361+P353-P304+P340-P305+P354+P338-P316-P317-P321-P330-P362+P364-P363-P370+P378-P402+P404-P403+P235-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	4	H332
Acute toxicity	Acute Tox.	4	H312
Substances or mixtures which in contact with water emit flammable gases	Water-react.	1	H260
Flammable liquids	Flam. Liq.	3	H226
Skin corrosion	Skin Corr.	1B	H314
Serious eye damage	Eye Dam.	1	H318
Skin corrosion	Skin Corr.	1	H314
Substances or mixtures which in contact with water emit flammable gases	Water-react.	2	H261
Specific target organ toxicity - single exposure	STOT SE	3	H335

Discovory and Applicatios

Diiodosilane (SiH₂I₂) is an inorganic silicon compound consisting of a silicon atom bonded to two hydrogen atoms and two iodine atoms. It appears as a colorless to pale yellow liquid at room temperature and is sensitive to light and moisture. The compound is of interest in silicon chemistry because the presence of iodine atoms on silicon makes it a useful intermediate for synthesizing other organosilicon and inorganic silicon compounds.

Diiodosilane can be prepared by halogen exchange reactions, typically starting from dichlorosilane (SiH₂Cl₂) or dibromosilane (SiH₂Br₂) and treating them with an iodide source such as sodium iodide in an aprotic solvent like acetone. Another synthetic approach involves the direct iodination of silanes under controlled conditions. Due to its susceptibility to decomposition when exposed to light, diiodosilane is usually handled under inert atmosphere and stored in amber-colored containers to minimize photodegradation.

The high reactivity of the Si–I bond in diiodosilane makes it a versatile precursor for further chemical transformations. It can be used to introduce silicon into organic molecules via reactions with organometallic reagents such as Grignard reagents or organolithium compounds, forming organosilanes after substitution of the iodine atoms. Diiodosilane is also employed in the synthesis of silicon-based polymers and materials, where its reactivity allows for controlled incorporation of silicon units.

In semiconductor and materials science, diiodosilane has been explored as a gaseous or liquid precursor for depositing silicon-containing films by chemical vapor deposition (CVD) and related methods. The relatively weak Si–I bond facilitates decomposition at lower temperatures compared to other silicon halides, which can be advantageous for thin-film growth on temperature-sensitive substrates.

Due to its sensitivity to moisture, diiodosilane reacts readily with water, producing hydrogen iodide and silanols, and eventually forming silicon dioxide. This reactivity, along with its flammability and potential release of corrosive hydrogen iodide, necessitates careful handling under dry, inert conditions. Protective measures include working in an inert-gas glovebox or using rigorously dried glassware and solvents.

While diiodosilane is not a high-volume industrial chemical, it serves as a valuable specialty reagent in silicon chemistry, both in laboratory-scale syntheses and in certain materials applications that require highly reactive silicon sources.

References

2024. Method for removing trace organic matters in diiodosilane. Publication Number: CN-118851183-A. Priority Date: 2024-09-25.

2024. Preparation method of diiodosilane. Publication Number: CN-118579792-A. Priority Date: 2024-06-04.

2024. A distillation and purification method for diiodosilane. Publication Number: CN-118458783-A. Priority Date: 2024-05-21.