Loss on Ignition (LoI) is not a chemical but rather a test that measures the mass lost by a material when heated to a high temperature. The material is typically heated to between 550 and 950 degrees Celsius, and the mass lost is measured as a percentage of the original sample weight.

The LoI test is often used to determine the amount of volatile components in a material, such as water, ash, and organic matter. It can also be used to identify the presence of inorganic compounds, such as carbonates, sulfates, and nitrates.

The LoI test is a simple and inexpensive test that can provide valuable information about the composition of a material. It is often used in conjunction with other tests, such as X-ray diffraction and chemical analysis, to obtain a complete understanding of a material's properties.