Abstract: A solid electrolyte having high electrical conductivity even in a low-temperature region is provided. A solid electrolyte containing a hexagonal perovskite-related compound, in which the compound is a compound represented by the following general formula (1), and an electrolyte layer and a battery using the solid electrolyte are disclosed. Ba7-?Nb(4?x-y)Mo(1+x)MyO(20+z) (1), in the formula (1), M is a cation of at least one element; a represents a Ba deficiency amount and represents a value of 0 or more and 0.5 or less, x represents a value of ?1.1 or more and 1.1 or less, y represents a value of 0 or more and 1.1 or less, and z represents an oxygen non-stoichiometry and represents a value of ?2.0 or more and 2.0 or less, provided that in the formula (1), |x|+y?0.01 is satisfied.

Abstract: Perovskite related compound of the present invention have layered structures in which perovskite units and A-rare earth structure units are alternately arranged. The reduced cell parameters ar-cr and ?r-?r and the reduced cell volume Vr are within the following ranges: ar=6.05±0.6 ?, br=8.26±0.8 ?, cr=9.10±0.9 ?, ?r=103.4±10°, ?r=90±10°, ?r=90±10°, and Vr=442.37±67 ?3. At least one of the reduced cell parameters ar-cr can be m/n times as large as the aforementioned values, where m and n are independent natural numbers, the square roots of 2 or 3 or integral multiples thereof. Values of ar, br and cr can be replaced with one another, or values of ?r, ?r and ?r can be replaced with one another.

Abstract: Perovskite related compound of the present invention have layered structures in which perovskite units and A-rare earth structure units are alternately arranged. The reduced cell parameters ar-cr and ?r-?r and the reduced cell volume Vr are within the following ranges: ar=6.05±0.6 ?, br=8.26±0.8 ?, cr=9.10±0.9 ?, ?r=103.4±10°, ?r=90±10°, ?r=90±10°, and Vr=442.37±67 ?3. At least one of the reduced cell parameters ar-cr can be m/n times as large as the aforementioned values, where m and n are independent natural numbers, the square roots of 2 or 3 or integral multiples thereof. Values of ar, br and cr can be replaced with one another, or values of ?r, ?r and ?r can be replaced with one another.