Standard X-ray Diffraction Powder Patterns

Erbium Arsenate, ErAsO4 (tetragonal)Powder data cards. None.Additional published patterns. None.NBS sample. The sample of erbium arsenatewas prepared at NBS from a water solution ofarsenic pentoxide and erbium trichloride. Spectrographicanalysis showed the following majorimpurities: 0.01 to 0.1 percent each of nickel andantimony and 0.001 to 0.01 percent each ofaluminum, calcium, magnesium, lead, and silicon.The sample was very pale pink. The indicesof refraction could not oe determined becausethe sample was too fine.The &-values of the three strongest lines are:3.510, 2.652, and 1.812 i.Structural data. Durif and Forrat [1] in 1957determined that erbium arsenate has the zirconstructure with the space group DIS-I(No. 141) and 4(ErAsO4 ) per unit cell.19571963Lattice constantsDurif and Forrat [!]__-__National Bureau ofStandards at 25 °C.aA7.047. 0203±. 0002cA6.306. 2761± . 0004The density of erbium arsenate calculated fromthe NBS lattice constants is 6.574 g/cm3 at 25 °C.Reference[1] A. Durif and F. Forrat, Sur quelques ars6niates desterres rares & structure zircon, Compt. Rend.1636-38 (1957).hkl101200211112220202301103321312400213411420332204501224512440600, 404532620, 424116613640, 444712, 316604624732800820516660752Internal Standard,Tungsten, a = 3. 1648 ACu, 1.5405 A at 25 CdA4. 6793.5102, 8052. 6522. 4812. 3392. 1932.0051. 8591. 8121. 7551. 7411. 6431. 56981. 46381. 4328L 37021. 32641. 26101. 24111. 17011. 12401. 10981. 02341. 01090. 9734.9465.9380. 9062. 8845. 8777. 8516. 8329. 8274. 7898I12100468202857521442151491810377123