Lead metaborate (PbB2O4· H2O) is a white crystalline powder with some toxicity. It is an inorganic compound that is commonly used in the manufacture of lead glass, fire retardant coatings, desiccant for paints and inks, and in the solder agent and enamel industries.

1. Lead glass manufacturing: Lead metaborate is one of the important components of lead glass, which is used to improve the refractive index and transparency of glass.

2. Desiccants for fire-retardant coatings, paints and inks: Due to its good heat resistance and dryness, lead metaborate is used as a desiccant for these products.

3. Flux: During the soldering process, lead metaborate can be used as a flux to help the soldering material melt and join.

4. Enamel industry: Lead metaborate is used in enamel products to improve its heat resistance and durability.

5. Other applications: Lead metaborate is also used in ceramics, electronics, and other industrial applications.