Silicon Tetrachloride Storage & Tank Compatibility

Storing Silicon Tetrachloride? Start Here

Silicon tetrachloride (SiCl₄) is a colorless, fuming liquid with a sharp, suffocating odor, used primarily as a feedstock for high-purity silicon, fumed silica, and optical-fiber preforms. It is an anhydrous reactive chlorosilane: on contact with water or even moist air it hydrolyzes vigorously, releasing dense clouds of corrosive hydrogen chloride and generating heat. Because of this reactivity, silicon tetrachloride is never stored in polyethylene tanks. It is handled in dedicated dry, inert-gas-blanketed systems built from glass-lined or lined metal vessels with PTFE seals. This page summarizes its hazard profile and material compatibility so engineers can specify the right containment. Polyethylene tanks listed on this site are engineered for aqueous and water-compatible chemistries, not for reactive chlorosilane service such as SiCl₄.

Can You Store Silicon Tetrachloride in HDPE or XLPE Tanks?

No. Silicon tetrachloride is an anhydrous reactive chlorosilane, and polyethylene tanks (HDPE and crosslinked XLPE) are rated Unsuitable (U) for this service. Two issues compound here: first, any trace of moisture that reaches the chemical triggers rapid hydrolysis, evolving hydrogen chloride gas and heat that attack fittings, gaskets, and vent paths; second, reactive chlorosilanes are simply outside the design envelope of polyethylene storage tanks, which are built for aqueous and water-based chemistries. Standard chemical-resistance charts class reactive chlorosilanes as not recommended for polyethylene. Silicon tetrachloride is stored instead in dedicated dry, inert-blanketed glass-lined or lined-metal equipment with PTFE sealing. If your process involves silicon tetrachloride, contact us about the correct containment rather than a polyethylene tank.

Material compatibility at a glance

Silicon tetrachloride is an anhydrous reactive chlorosilane that hydrolyzes violently on contact with water or humid air, releasing corrosive hydrogen chloride gas and heat. It is not a candidate for polyethylene (HDPE/XLPE) storage tanks. Industry stores it in dedicated dry, inert-blanketed metal (lined or stainless) or glass-lined equipment with PTFE seals. Polyethylene tanks shown on this site are intended for aqueous and many water-based chemistries, not reactive chlorosilanes.

Ratings: S suitable · C conditional / limited · U unsuitable. Verify against the cited resistance charts and your concentration/temperature before specifying.

The safety that actually matters

• Reacts violently with water and humid air, releasing corrosive hydrogen chloride gas and heat - keep strictly anhydrous and blanket with dry inert gas.
• Toxic if swallowed or inhaled (H301, H331); use closed handling and adequate ventilation or local exhaust.
• Causes severe skin burns and eye damage (H314, H318); wear chemical goggles, face shield, and acid-resistant gloves and apron.
• Vapors and hydrolysis fumes cause respiratory irritation and organ damage (H335, H370, H371); use respiratory protection rated for acid gases.
• Noncombustible itself, but corrosive HCl mist and contact with metals can generate flammable hydrogen - keep ignition sources away during any spill.
• Store away from water, alcohols, bases, and amines; have acid-gas spill control and emergency eyewash and safety shower available.

Common questions

Is silicon tetrachloride compatible with polyethylene (HDPE/XLPE) tanks?

No. It is an anhydrous reactive chlorosilane and is rated Unsuitable (U) for polyethylene. Trace moisture liberates corrosive hydrogen chloride, and polyethylene is not designed for reactive chlorosilane service. Use dedicated dry, inert-blanketed glass-lined or lined-metal equipment.

What happens when silicon tetrachloride contacts water?

It hydrolyzes violently, producing hydrogen chloride gas and heat (and silica). This is why it must be kept anhydrous and away from moist air, and why NFPA 704 assigns it the W (water-reactive) special hazard.

Is silicon tetrachloride flammable?

The liquid itself is noncombustible (NFPA flammability 0 and no flash point). However, hydrogen chloride generated on contact with metals during a spill can form flammable hydrogen, so ignition sources should be controlled.

What is the NFPA 704 rating for silicon tetrachloride?

Health 3, Flammability 0, Instability 2, with the special hazard W for water-reactive, per CAMEO Chemicals (NOAA).