Institute of Experimental Mineralogy
                 Russian Academy of Sciences
     -------------------------------------------------
           142432, Chernogolovka, Moscow district
             A.V. Chichagov  +7(496)52-22320

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          ***      W W W - X R A Y P O L       ***
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NIOBIUM

1, at 18'C

Nb


Cubic  I m3m  Z = 2

Im3m

27 .5 .1993

Ref.Str.:

         Wyckoff R.W.G. (1963)

         * Crystal Structures, 1, 15-16

         R: ATOMIC. N.A.D.

                   Initial data from BDM-file 

   Lattice parameters (cub. angs.,degr.):

             a =   3.3004   alpha =   90.0 
             b =   3.3004   beta  =   90.0 
             c =   3.3004   gamma =   90.0 

    Unit cell volume (cub. angs.) =    35.95

    Molar volume ( cub.cm/mol.) =    10.83

  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    Nb    = 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       1     0.5        0.5        0.5   


X-ray density (g/cm cub.)   =      8.58

MU (1/cm) =    1312.724    Mass attenuation coefficient (cm**2/g) =    153.0  

 Selected interatomic distances (cation-anion,anion-anion):

 NoP    Atom              Rad.sph.      C.N.    Distance     NoP N.
                           (angs.)               (angs.)

    1    Nb                  3.48        14
                                                 3.3004       1
                                                 3.3004       1
                                                 3.3004       1
                                                 3.3004       1
                                                 3.3004       1
                                                 3.3004       1
                                                 2.8582       1
                                                 2.8582       1
                                                 2.8582       1
                                                 2.8582       1
                                                 2.8582       1
                                                 2.8582       1
                                                 2.8582       1
                                                 2.8582       1

  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   0 19.273  38.545   0.214   15.67   12       62.7    57297.7
    2   2   0   0 27.825  55.651   0.303    6.84    6       54.8     9537.4
    3   1   1   2 34.868  69.736   0.371    4.18   24       49.6    19110.5
    4   2   2   0 41.31   82.619   0.428    3.11   12       46.0     6101.4


  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   0  19.273  38.545  2.33374    57297.7    100.0    100.0     5.7
    2   2   0   0  27.825  55.651  1.6502      9537.4     16.6     16.3     5.8
    3   1   1   2  34.868  69.736  1.34738    19110.5     33.4     32.0     5.9
    4   2   2   0  41.31   82.619  1.16687     6101.4     10.6      9.9     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)