University of Colorado

Mineral Structure and Property Data

Barite Group


The barite group is composed of the minerals barite (BaSO4), celestite (SrSO4), and anglesite (PbSO4).

The crystal structure of barite.


                Barite      Celestite   Anglesite
                BaSO4       SrSO4        PbSO4

Form.Wt. 233.40 183.68 303.25 Z 4 4 4 CrystalSystem Orth Orth Orth PointGroup mmm mmm mmm SpaceGroup Pbnm Pbnm Pbnm UnitCell a(Å) 7.157 6.870 6.959 a(Å) 8.884 8.371 8.482 c(Å) 5.457 5.355 5.398 Vol(Å3) 346.97 307.96 318.62 MolarVol 52.245 46.371 47.977 Density 4.467 3.961 6.321 Thermal Expansion(Volumetric) alpha 63.7 a0 0.6370 a1 0.0000 a2 0.0000

Barite Group M Sites



End-Member         Celestite         Anglesite         Barite

C.N.               10                10                10
Occupant           Sr                Pb                Ba

Point Sym.         m                 m                 m
Wyckoff Not.       4c                4c                4c

Frac.Coord.
x                  .1583             .1667             .1585
y                  .1839             .1879             .1845
z                  1/4               1/4               1/4

Distances
Cation-Ox
O1(1)              2.536             2.613             2.770
O2(2)              2.980             3.005             3.075
O2(1)              2.636             2.619             2.798
O3(2)              2.690             2.648             2.811
O3(2)              2.653             2.737             2.811
O3(2)              2.816             2.910             2.911

Mean               2.745             2.783             2.879
sigma              .149             .159               .113

Poly.Vol.          45.90            47.97              52.99

Site Energy        -953.            -939.              -892.


Barite Group S Sites



End-Member         Celestite         Anglesite         Barite

C.N.               4                 4                 4
Occupant           S                 S                 S


Point Sym.         m                 m                 m
Wyckoff Not.       4c                4c                4c

Frac.Coord.
x                  .1853             .1842             .1911
y                  .4382             .4367             .4375
z                  1/4               1/4               1/4

Distances 
O1(1)              1.452             1.453             1.468
O2(1)              1.472             1.481             1.470
O3(2)              1.486             1.497             1.486

Mean               1.474             1.482             1.478
sigma              .016              .021              .010 

Poly.Vol.          1.643             1.669             1.655
Q.E.               1.0005            1.0012            1.0004
Ang.Var.           2.31              5.20              2.01

Site Energy        -9648.            -9590.            -9622.



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