Machinable Dy-containing beta-Ca3(PO4)2 ceramics

The crystal structure of a layered perovskite compound, BaGd2Mn2O7, was analyzed for the powder X-ray diffraction data by Rietveld method. The tetragonal BaGd2Mn2O7 phase has superlattice lines so that the space group of P42/mnm (No. 136) was determined with the unit cell dimensions a=0.55024(1) and c=2.02457(5) nm. The MnO6 octahedron was distorted and tilts by 6° apart from the c axis mutually in the reverse direction.