Nanopowders are powders composed of nanoparticles having an average diameter below 50 nanometers and many a time below 30 nm. True nanoparticles exist as free to move relative to each other and accordingly when not in liquid suspension resemble like smoke particles. This can be imagined physically that, a jar of a true nanopowder when emptied from one meter height to toward the ground will disperse into the air before reaching the floor. It is said that most manufacturers of “nanopowders” produce micropowder assemblies of nanoparticles but the powder itself is rarely a nanopowder. A complex nanopowder is a nanopowder where each individual particle is composed of a complex chemical compound. Such compounds have two or more different cations (positively charged elements) in their chemical formula. An example of a complex compound is calcium titanate (CaTiO3). For every application of nanopowders having simple (single cation) composition, there can be more than 100 applications for nanopowders having complex composition (multi cation). A small list of commercially available nanopowder compositions is as below:

COMPLEX OXIDES & CHEMICAL FORMULA

Aluminum titanate Al2TiO5

Barium aluminum titanate Ba1.23Al2Ti5.54O16

(11) Barium copper oxide BaCuO2

(212) Barium calcium copper oxide Ba2CaCu2O5

(23) Barium copper oxide Ba2Cu3O5

(223) Barium calcium copper oxide Ba2Ca2Cu3O5

Barium strontium titanium oxide BaSrTi2O6

Calcium titanate CaTiO3

Calcium zirconium titanium oxide CaZrTi2O3

Cadmium tungsten oxide CdWO4 Cerium aluminate CeAlO3

Copper aluminate CuAl2O4

Iron nickel oxide FeNiO4

Lanthanum chromite LaCrO3

(lanthanum chromium (III) oxide LaCrO3)

Lanthanum manganite LaMnO3

(lanthanum manganese (III) oxide LaMnO3)

Lanthanum substituted lithium titanate (LaLi3)TiO3

Nickel cobalt oxide NiCoO2

Strontium bismuth niobium oxide SrBi2Nb2O9

Strontium ferrite SrFe12O19

Strontium vanadium substituted niobium oxide Sr2(Nb,V)2O7

Yttrium aluminum oxide Y3Al5O12

Yttrium iron oxide Y3Fe5O12

Zinc iron oxide ZnFe2O4

Zinc titanium oxide ZnTiO3

Zirconium titanium Iron(III) aluminate ZrTi3FeAlO7

Zirconium titanium aluminate ZrTi2Al2O5