An article comprises a body having a coating. The coating comprises a M-O-F coating having a molar O/F ratio that is customized to future processing that the article may be exposed to.

An yttrium oxyfluoride is represented by YOF and is stabilized by a fluoride represented by CaF.sub.2. Preferably, the number of moles of Ca with respect to 100 mol of yttrium is from 8 to 40 mol. A powder material is made of a first powder mixture including a calcium fluoride powder represented by CaF.sub.2 and an yttrium oxyfluoride powder represented by YOF, or a second powder mixture including a calcium fluoride powder represented by CaF.sub.2, an yttrium fluoride powder represented by YF.sub.3, and an yttrium oxide powder represented by Y.sub.2O.sub.3. A production method involves firing a molded product of the first or second powder mixture under predetermined conditions.

An yttrium oxyfluoride is represented by YOF and is stabilized by a fluoride represented by CaF.sub.2. Preferably, the number of moles of Ca with respect to 100 mol of yttrium is from 8 to 40 mol. A powder material is made of a first powder mixture including a calcium fluoride powder represented by CaF.sub.2 and an yttrium oxyfluoride powder represented by YOF, or a second powder mixture including a calcium fluoride powder represented by CaF.sub.2, an yttrium fluoride powder represented by YF.sub.3, and an yttrium oxide powder represented by Y.sub.2O.sub.3. A production method involves firing a molded product of the first or second powder mixture under predetermined conditions.

A luminophore having the empirical formula A.sub.3M*O.sub.xF.sub.9-2x:Mn.sup.4+ where A may be or include Li, Na, Rb, K, Cs, or combinations thereof. M* may be or include Cr, Mo, W, or combinations thereof. x may be or include 0<x<4.5.

A luminophore having the empirical formula A.sub.3M*O.sub.xF.sub.9-2x:Mn.sup.4+ where A may be or include Li, Na, Rb, K, Cs, or combinations thereof. M* may be or include Cr, Mo, W, or combinations thereof. x may be or include 0<x<4.5.

A battery includes a positive electrode containing a positive electrode active material, a negative electrode, and a solid electrolyte. The positive electrode active material contains a compound which has a crystal structure belonging to the space group FM3-M and which is represented by the following formula:

Li.sub.xMe.sub.yO.sub.F.sub.(1)

where Me is one or more selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V and Cr and the conditions 1.7x2.2, 0.8y1.3, 12.5, and 0.52 are satisfied.

A battery includes a positive electrode containing a positive electrode active material, a negative electrode, and a solid electrolyte. The positive electrode active material contains a compound which has a crystal structure belonging to the space group FM3-M and which is represented by the following formula:

Li.sub.xMe.sub.yO.sub.F.sub.(1)

where Me is one or more selected from the group consisting of Mn, Co, Ni, Fe, Al, B, Ce, Si, Zr, Nb, Pr, Ti, W, Ge, Mo, Sn, Bi, Cu, Mg, Ca, Ba, Sr, Y, Zn, Ga, Er, La, Sm, Yb, V and Cr and the conditions 1.7x2.2, 0.8y1.3, 12.5, and 0.52 are satisfied.

A thermal spray material comprising granules containing a rare earth oxyfluoride has a particle diameter of 1 to 150 m at a cumulative volume of 50 vol % before ultrasonic dispersion and 10 m or smaller after ultrasonic dispersion at 300 W for 15 minutes as determined by laser diffraction/scattering particle size distribution analysis. The particle diameter after ultrasonic dispersion is one-third or less of that before ultrasonic dispersion. The thermal spray material has an average aspect ratio of 2.0 or lower and a compressibility of 30% or less. When the granules further contain a rare earth fluoride, upon being analyzed by X-ray diffractometry using Cu-K or Cu-K1 radiation, S1/S2 is preferably 0.10. S1=intensity of the maximum peak assigned to the rare earth oxyfluoride. S2=intensity of the maximum peak assigned to the rare earth fluoride, both observed in a 2 angle range of 20 to 40.

A thermal spray material comprising granules containing a rare earth oxyfluoride has a particle diameter of 1 to 150 m at a cumulative volume of 50 vol % before ultrasonic dispersion and 10 m or smaller after ultrasonic dispersion at 300 W for 15 minutes as determined by laser diffraction/scattering particle size distribution analysis. The particle diameter after ultrasonic dispersion is one-third or less of that before ultrasonic dispersion. The thermal spray material has an average aspect ratio of 2.0 or lower and a compressibility of 30% or less. When the granules further contain a rare earth fluoride, upon being analyzed by X-ray diffractometry using Cu-K or Cu-K1 radiation, S1/S2 is preferably 0.10. S1=intensity of the maximum peak assigned to the rare earth oxyfluoride. S2=intensity of the maximum peak assigned to the rare earth fluoride, both observed in a 2 angle range of 20 to 40.

An object of the present invention is to provide a new nanogranular structure material having magneto-optical properties different from those of existing nanogranular structure materials, and a method for producing the same. The nanogranular structure material has a composition represented by L-M-FO wherein L is at least one element selected from the group consisting of Fe, Co, and Ni, and M is at least one element selected from the group consisting of Li, Be, Mg, Al, Si, Ca, Sr, Ba, Bi, and rare earth elements, F is fluorine, and O is oxygen. The nanogranular structure material according to the present invention is composed of a matrix formed of a fluorine compound having a composition represented by M-F and metal oxide nanoparticles dispersed in the matrix and having a composition represented by L-O.