Abstract: A layered body includes: a substrate; and an oxide portion positioned on the substrate. An oxide that constitutes the oxide portion contains at least two or more rare-earth elements: silicon; and oxygen. The oxide that is contained in the oxide portion exhibits a diffraction peak derived from a (004) plane at a position of 2?=51.9°±0.9° in an X-ray diffraction pattern, and has an apatite crystal structure. The ratio of linear expansion coefficient of the oxide that constitutes the oxide portion in an a-axis direction relative to linear expansion coefficient of the substrate is 0.15 or more and 1.45 or less.

Abstract: An oxygen permeable element includes an anode, a cathode, and a solid electrolyte. With a voltage applied between the anode and the cathode, oxygen gas in the cathode side atmosphere is allowed to pass through the solid electrolyte to the anode side. The oxygen permeable element has interlayers located between the solid electrolyte and at least one of the cathode and the anode, at least one interlayer containing an oxide of bismuth. The solid electrolyte contains an oxide of lanthanum.