Institute of Experimental Mineralogy Russian Academy of Sciences ------------------------------------------------- 142432, Chernogolovka, Moscow district A.V. Chichagov +7(496)52-22320 *** *** W W W - X R A Y P O L *** *********************** VILLIAUMITE 3, t-halite, syn, at 176'C, g-villiaumite NaF Cubic F m3m Z = 4 Fm3m 8 .10 .12 Ref.Str.: Deshpande V.T. (1961) * Acta Cryst., 14, 794-794 R: In the article there are structure data for synthetic villiaumite at different temperatures from 29.6'C up to 254'C. N.A.D. Initial data from BDM-file Lattice parameters (cub. angs.,degr.): a = 4.6585 alpha = 90.0 b = 4.6585 beta = 90.0 c = 4.6585 gamma = 90.0 Unit cell volume (cub. angs.) = 101.1 Molar volume ( cub.cm/mol.) = 15.22 Co-ordinates, thermal parameters, occupation for atomic positions: NoP x/a y/b z/c B(j) atom / occupation 1 0.0 0.0 0.0 0.0 Na = 1.00 2 0.5 0.5 0.5 0.0 F = 1.00 Co-ordinates for all atomic positions : No NoP x/a y/b z/c 1 1 0.0 0.0 0.0 2 2 0.5 0.5 0.5 3 1 0.5 0.0 0.5 4 1 0.5 0.5 0.0 5 1 0.0 0.5 0.5 6 2 0.0 0.5 0.0 7 2 0.0 0.0 0.5 8 2 0.5 0.0 0.0 X-ray density (g/cm cub.) = 2.76 MU (1/cm) = 65.914 Mass attenuation coefficient (cm**2/g) = 23.901 Selected interatomic distances (cation-anion,anion-anion): NoP Atom Rad.sph. C.N. Distance NoP N. (angs.) (angs.) 1 Na 2.772 6 2.3293 2 2.3293 2 2.3293 2 2.3293 2 2.3293 2 2.3293 2 2 F 3.192 0 X-ray diffraction powder data (II), X-Ray W.L. = 1.54056(angs.): No H K L Theta 2*Theta S LPG MF F I int. ( degree ) *100 1 1 1 1 16.642 33.284 0.186 21.62 8 6.6 73.0 2 2 0 0 19.311 38.622 0.215 15.6 6 59.2 3208.9 3 2 2 0 27.884 55.767 0.304 6.81 12 48.2 1855.4 4 1 1 3 33.257 66.515 0.356 4.61 24 7.4 59.7 5 2 2 2 34.945 69.89 0.372 4.16 8 40.6 535.9 6 4 0 0 41.407 82.813 0.429 3.1 6 35.1 223.7 X-ray diffraction powder data (I)...X-Ray wave length = 1.54056 (angs.): No H K L Theta 2*Theta d I int I int.n. I p.h.n. H(Si) ( degree ) (angstrem) *100 *100 1 1 1 1 16.642 33.284 2.68959 73.0 2.3 2.3 5.6 2 2 0 0 19.311 38.622 2.32925 3208.9 100.0 100.0 5.7 3 2 2 0 27.884 55.767 1.64703 1855.4 57.8 56.7 5.8 4 1 1 3 33.257 66.515 1.40459 59.7 1.9 1.8 5.9 5 2 2 2 34.945 69.89 1.34479 535.9 16.7 16.0 5.9 6 4 0 0 41.407 82.813 1.16462 223.7 7.0 6.5 6.1 Reference: Chichagov A.V. et al. Information-Calculating System on Crystal Structure Data of Minerals (MINCRYST) - Kristallographiya, v.35, n.3, 1990, p.610-616 (in Russian) |