Tungsten diiodide (WI₂) is an inorganic compound composed of the transition metal element tungsten and the halogen element iodine. It has many chemical properties, which will be described one by one below.

A small amount of tungsten diiodide has low theoretical toxicity and will not harm health.

A tungsten iodide lamp is a kind of tungsten lamp filled with the halogen element iodine and belongs to a new generation of incandescent lamps In an iodine-tungsten lamp, the evaporation of iodine-tungsten circulating tungsten is effectively suppressed, and the problem of blackening glass shell is solved.Iodine tungsten lamp as a thermal radiation source has some potential safety hazards, so there are corresponding requirements and precautions for its installation and use.

There are tungsten vapor, iodine vapor, tungsten iodide gas and inert gas in the iodine tungsten lamp.

The tungsten filament of a tungsten iodine lamp is a conductor and can radiate visible light. A tungsten iodine lamp is a new type of electric light source, the main components are the internal tungsten filament and the external glass shell. Under the action of electric current, the spiral tungsten filament continuously gathers heat, making the temperature of the filament reach over 2000℃. Microscopically, the tungsten atom's electrons outside the nucleus are excited by heat to a high-energy state, to maintain stability and fall back to a low-energy state, the energy difference in the form of photons released, macroscopically visible luminescence phenomenon.

An iodine tungsten lamp is a kind of high-efficiency lighting fixture, which is generally composed of tungsten wire and quartz glass shell. Because of its small size and high internal temperature, the glass shell will undergo a cycle of "melting-cooling-solid reheating" after use. If there is an impurity attached to the bulb shell and the surface treatment is not carried out in time, the atomic arrangement of quartz glass will change at high temperatures, causing the surface to crystallize and lose its transparency. This phenomenon is called devitrification.

Quartz glass can be used as bulb shell of iodine tungsten lamp.Iodine tungsten lamp is one of the first choice products in green lighting engineering in China. It has the characteristics of high light efficiency, small volume and energy saving, and is suitable for the design and shape of various lamps and lanterns. It is widely used in lighting field.

Ordinary glass cannot be used as a bulb shell for an iodine tungsten lamp. The iodine tungsten lamp is a kind of illumination lamp that uses the principle of halogen-tungsten circulation to fill iodine into the bulb to control the sublimation of the tungsten wire. It has the characteristics of high brightness and long life. It is often used as the light source of cinematography stage factory building square.

Iodine tungsten lamp is not allowed to be used on the construction site. Iodine tungsten lamp is an improved version of incandescent lamps. Its principle is similar to that of incandescent lamp. A chemical combination reaction occurs at the lamp wall, and the sublimated tungsten on the lamp wall and other parts of the lamp tube is recycled to the filament and sublimated at a relatively high temperature (above 1200-2000℃) so that the filament will not burn out quickly due to high temperature.

Iodine tungsten lamp has ignition capacity. An iodine tungsten lamp is a kind of tungsten filament lamp filled with iodine vapor for a chemical reaction. It is often used in indoor and outdoor lighting places with high illumination requirements and high installation points. This kind of lamp has a high degree of thermal light source, and there is a risk of burning combustibles on the outer wall of the lamp tube in a short time. Therefore, it is of great significance to understand the ignition ability of iodine tungsten lamp to combustibles for fire prevention and fire investigation.