Nanoplatelet forms of metal hydroxide and metal oxide are provided, as well as methods for preparing same. The nanoplatelets are suitable for use as fire retardants and as agents for chemical or biological decontamination.

The present invention relates to -Al.sub.2O.sub.3 flakes prepared by a process comprising (1) preparation of an aqueous solution of at least one water-soluble and/or insoluble aluminum salt which optionally contains at least one sulfate compound, (2) adding a basic solution and optionally at least one dopant to the aluminum salt solution (1), (3) drying of the obtained gel, followed by calcination to obtain Al2 03 flakes and alkali salts in a molten salt, and (4) removal of the water soluble parts of the calcined molten salt obtained in step (3).

Nanoplatelet forms of metal hydroxide and metal oxide are provided, as well as methods for preparing same. The nanoplatelets are suitable for use as fire retardants and as agents for chemical or biological decontamination.

A process for the production of flake-form, crystalline particles having an aurivillius structure, the use thereof as effect pigments or as substrates of effect pigments, furthermore, effect pigments which contain coated or uncoated flake-form, crystalline particles having an aurivillius structure as substrates, and the use thereof in various products.

A new material efficiently attenuating transmission of near-infrared light is provided. A provided near-infrared-shielding material includes a plurality of flaky particles, wherein each of the plurality of flaky particles includes a flaky substrate and a single-layer film formed on a principal surface of the flaky substrate, and the near-infrared-shielding material has a light reflectance of 40% or more between wavelengths of 800 nm and 1400 nm. The flaky substrate is, for example, a glass flake. The glass flake has an average thickness of, for example, 0.6 m or less. The single-layer film includes, for example, titanium oxide and has an average thickness of, for example, 80 nm to 165 nm.