This paper reports a reference X-ray powder diffraction pattern for a high-pressure phase, CaCo2O4, which has been reported recently to have a large Seebeck coefficient. The structure of CaCo2O4 is orthorhombic with space group Pnma, a=8.789(2) Å, b=2.9006(7) Å, c=10.282(3) Å, V=262.43 Å3, and Dc=5.62 g/cm3. This phase crystallizes in the CaFe2O4-type structure and consists of an edge- and corner-shared CoO6 octahedral network. The reference pattern has been submitted to the Powder Diffraction File (PDF).
