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
4, t-halite, syn, at 254'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 = 4.6726 alpha = 90.0
b = 4.6726 beta = 90.0
c = 4.6726 gamma = 90.0
Unit cell volume (cub. angs.) = 102.02
Molar volume ( cub.cm/mol.) = 15.36
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.) = 2.73
MU (1/cm) = 65.319 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
2.3363 2
2.3363 2
2.3363 2
2.3363 2
2.3363 2
2.3363 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 16.59 33.181 0.185 21.76 8 6.6 72.0
2 2 0 0 19.251 38.501 0.214 15.71 6 59.3 3182.0
3 2 2 0 27.792 55.585 0.303 6.86 12 48.3 1844.0
4 1 1 3 33.144 66.288 0.355 4.64 24 7.4 59.1
5 2 2 2 34.824 69.648 0.371 4.19 8 40.7 533.0
6 4 0 0 41.254 82.509 0.428 3.11 6 35.2 222.2
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 16.59 33.181 2.69773 72.0 2.3 2.3 5.6
2 2 0 0 19.251 38.501 2.3363 3182.0 100.0 100.0 5.7
3 2 2 0 27.792 55.585 1.65201 1844.0 58.0 56.8 5.8
4 1 1 3 33.144 66.288 1.40884 59.1 1.9 1.8 5.9
5 2 2 2 34.824 69.648 1.34886 533.0 16.8 16.1 5.9
6 4 0 0 41.254 82.509 1.16815 222.2 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)
|