They are coordination polymers consisting of zinc(II) centers bonded to cyclic boron oxide rings.

Zinc borate is primarily used as a flame retardant in plastics and cellulose fibers, paper, rubbers and textiles.

As a flame retardant, it can replace antimony(III) oxide as a synergist in both halogen-based and halogen-free systems.

In halogen-free system, zinc borate can be used together with alumina trihydrate, magnesium hydroxide, red phosphorus, or ammonium polyphosphate.

[4] Zinc borate is used in polyvinyl chloride, polyolefins, polyamides, epoxy resins, polyesters, thermoplastic elastomers, rubbers, etc.