Provided is a novel polyoxometalate and a method for producing the polyoxometalate. The polyoxometalate is represented by the compositional formula: M.sub.xO.sub.y in which M is tungsten, molybdenum or vanadium; 4x1000; and 2.5y/x7.

A mixed conductor represented by Formula 1:

A.sub.4+xM.sub.5-yM.sub.yO.sub.12-,Formula 1

wherein, in Formula 1, A is a monovalent cation, M is at least one of a divalent cation, a trivalent cation, or a tetravalent cation, M is at least one of a monovalent cation, a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, or a hexavalent cation, M and M are different from each other, and 0.3x<3, 0.01<y<2, and 01 are satisfied.

Methods of increasing the particle size of ammonium octamolybdate (AOM) pigment powder are provided. A method can include heating the AOM pigment powder to a temperature above 20 C. for a given amount of time. An ink composition can be produced by formulating AOM pigment powder with increased particle size and incorporating the AOM pigment powder into an ink composition.

A perovskite material represented by Formula 1:

Li.sub.xA.sub.yM.sub.zO.sub.3-Formula 1 wherein in Formula 1, 0<x1, 0<y1, 0<x+y<1, 0<z1.5, 01, A is H, Na, K, Rb, Cs, Ca, Sr, Ba, Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, or a combination thereof, and M is Ni, Pd, Pb, Fe, Ir, Co, Rh, Mn, Cr, Ru, Re, Sn, V, Ge, W, Zr, Mo, Hf, U, Nb, Th, Ta, Bi, Li, H, Na, K, Rb, Cs, Ca, Sr, Ba, Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Mg, Al, Si, Sc, Zn, Ga, Ag, Cd, In, Sb, Pt, Au, or a combination thereof.

A mixed conductor represented by Formula 1:

A.sub.xTi.sub.5yG.sub.zO.sub.12Formula 1 wherein, in Formula 1, A is a monovalent cation, G is at least one of a monovalent cation, a divalent cation, a trivalent cation, a tetravalent cation, a pentavalent cation, or a hexavalent cation, with the proviso that G is not Ti or Cr, wherein 0<x<2, 0.3<y<5, 0<z<5, and 0<3.

A spinel compound oxide particle includes metallic atoms, aluminum atoms, oxygen atoms, and molybdenum atoms, wherein the metallic atoms are selected from the group consisting of zinc atoms, cobalt atoms, and strontium atoms, and a crystallite size in a [111] plane is 100 nm or more. Included are a step (1) of firing a first mixture including a molybdenum compound and a metallic-atom-containing compound or a first mixture including a molybdenum compound, a metallic-atom-containing compound, and an aluminum compound to prepare an intermediate; and a step (2) of firing, at a temperature higher than a temperature selected in the step (1), a second mixture including the intermediate or a second mixture including the intermediate and an aluminum compound.

In general, according to one embodiment, there is provided an active material. The active material contains a composite oxide having an orthorhombic crystal structure. The composite oxide is represented by a general formula of Li.sub.2+wNa.sub.2xM1.sub.yTi.sub.6zM2.sub.zO.sub.14+. In the general formula, the M1 is at least one selected from the group consisting of Cs and K; the M2 is at least one selected from the group consisting of Zr, Sn, V, Nb, Ta, Mo, W, Fe, Co, Mn, and Al; and w is within a range of 0w4, x is within a range of 0<x<2, y is within a range of 0y<2, z is within a range of 0<z6, and is within a range of 0.50.5.

The invention relates to a substrate coated with a coating consisting of molybdenum (Mo), sulfur (S), tantalum (Ta) and oxygen (O) atoms present in the form of one or several compound(s) selected from among the compounds of formula (I):

Mo.sub.wS.sub.xTa.sub.yO.sub.z(I) wherein w is equal to 0 or 1; x varies from 0 to 2; y varies from 0 to 1 and z varies from 0 to 3; said coating comprising at least 5% at of oxygen and said coating having a dense compact microstructure.

To provide plate-like alumina particles that are less likely to wear apparatuses. Plate-like alumina particles containing germanium or a germanium compound. The plate-like alumina particles preferably have a molar ratio of Ge to Al, [Ge]/[Al], of 0.08 or more as determined in an XPS analysis. The plate-like alumina particles preferably contain the germanium or germanium compound in a surface layer. The plate-like alumina particles preferably have a density of 3.7 g/cm.sup.3 or more and 4.1 g/cm.sup.3 or less. The plate-like alumina particles preferably have a molar ratio of Ge to Al, [Ge]/[Al], of 0.08 or less as determined in an XRF analysis.

A negative thermal expansion material according to an embodiment is represented by a general formula (1): Cu.sub.2-xR.sub.xV.sub.2O.sub.7 (R is at least one element selected from Zn, Ga, and Fe) and includes an oxide sintered compact whose linear expansion coefficient is 10 ppm/K or less.