Standard X-ray Diffraction Powder Patterns

Holmium Arsenate, HoAsO4 (tetragonal)Powder data cards. None.Additional published patterns. None.NBS sample. The sample of holmium arsenatewas prepared at NBS from a water solution ofarsenic pentoxide ajid holmium trichloride. Spectrograpnicanalysis showed the following majorimpurities: 0.01 to 0.1 percent antimony and0.001 to 0.01 percent each of aluminum, calcium,iron, lead, and silicon.The color of the sample was very pale pinkishwhite. The indices of refraction could not bedetermined because the sample was too fine.The d-values of the three strongest lines are:3.528, 2.668, and 1.822 LStructural data. The structure of holmiumarsenate was not found in the literature; however,it is apparently isostructural with erbium arsenatehaving the space group DJg-l4i/amd (No. 141)and 4 (HoAsO4 ) per unit cell.Lattice constants1963 National Bureau of Standards at 25 °C.aA7. 0548±.0003cA6. 3159±.0005The density of holmium arsenate calculatedfrom NBS lattice constants is 6.420 g/cm3 at 25 °C.hkl101200211112220202301103321312400420332204501224413512440404, 600532424116206640552604624732800820516644660Internal Standard,Tungsten, a=3.1648 ACu 1.5405 A at 25 °CdA4.7093.5282.8192. 6682.4942.3522.2032.0171.8681.8221.7631. 57741. 47101. 44111. 37691. 33391. 32791. 26701. 24701. 17631, 12991. 11591. 03011. 00860. 9781. 9516.9428. 9110.8890.8818.8556.8378.8317. 8314751004672067545016141591949356103147234