Standard X-ray Diffraction Powder Patterns

Dysprosium Arsenate, DyAsO4 (tetragonal)Powder data cards. None.Additional published patterns. None.NBS sample. The sample of dysprosiumarsenate was prepared at NBS from a water solution of dysprosium trichloride and arsenicpentoxide. The sample was dried at 110 °C.Spectrographic analysis showed the followingmajor impurities: 0.01 to 0.1 percent antimonyana 0.001 to 0.01 percent each of calcium,magnesium, lead, and silicon.The sample is colorless. The indices ofrefraction could not be determined because thesample was too fine.The d-values of the three strongest lines are:3.537, 2.669, and 1.8246 A.Structural data. Durif and Forrat [1] in 1957determined that dysprosium arsenate has thezircon structure with tne space group Dih~/4i/amd(No. 141) and 4[DyAs(>4] per unit cell.19571963Lattice constantsDurif and Forrat [!]-_-National Bureau ofStandards at 25 °C.a0A7. 097. 0733±0. 0003c0A6. 3156. 3133±0. 0003The density of dysprosium arsenate calculatedfrom the NBS lattice constants is 6.338 g/cm3 at25 °C.Reference[1] A. Durif and F. Forrat, Sur quelques ars^niates desterres rares a structure zircon, Compt. Rend.1636-38 (1957).hkl101200211112220301103321312400213411420303332204501224512440600404532424631116415444552316604624Internal Standard,Silver, a=4.0861 ACo, 1.78891 at 25 Cd4.7133.5372.8282. 6692.5002.2092.017L 8731. 82461. 76811. 75221. 65561. 58121. 57021. 47401. 44131. 38021. 33451. 27011. 25041. 17901. 17731. 13231. 11721. 04001. 02971.01710. 9803. 9535. 9521. 9444. 9126i151003672288547143