| abstract |
An effective atomic number and density equivalent to those of a BaLu 2 F 8 single crystal, and without any phase transformation from an orthorhombic crystal structure to a monoclinic crystal structure, are efficient by a melt growth method. Provided is a fluoride single crystal that can be manufactured well. A chemical formula Ba (M x Y y Lu 1 -x-y) 2 F 8 ( although, M is Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb Represents at least one element selected, and x is in the range of 0 to 0.5, y is in the range of 0 to 0.8, and x and y are both 0). A fluoride single crystal having a monoclinic crystal structure and having an average ionic radius of the elements M, Y and Lu of 98.5 to 102.5 pm. [Selection figure] None |