data_2003323
_journal_name_full     'Acta Crystallographica'
_journal_year          1995
_journal_page_first    	555
_journal_page_last    	557
_publ_section_title    	
;
Cu-Bearing Tourmaline from Paraiba, Brazil
;
_chemical_formula_sum    	'Al8 B3 Li1 Na1 O31 Si6'
_chemical_formula_weight    	940.16
loop_
    _symmetry_equiv_pos_as_xyz
    'x,y,z'
    '-y,x-y,z'
    'y-x,-x,z'
    '-y,-x,z'
    'y-x,y,z'
    'x,x-y,z'
    '2/3+x,1/3+y,1/3+z'
    '2/3-y,1/3+x-y,1/3+z'
    '2/3+y-x,1/3-x,1/3+z''2/3-y,1/3-x,1/3+z'
    '2/3+y-x,1/3+y,1/3+z''2/3+x,1/3+x-y,1/3+z'
    '1/3+x,2/3+y,2/3+z'
    '1/3-y,2/3+x-y,2/3+z'
    '1/3+y-x,2/3-x,2/3+z''1/3-y,2/3-x,2/3+z'
    '1/3+y-x,2/3+y,2/3+z''1/3+x,2/3+x-y,2/3+z'
_symmetry_space_group_name_H-M    	'R 3 m {hexagonal axes}'
_cell_length_a    	15.818(2)
_cell_length_b    	15.818(2)
_cell_length_c    	7.087(1)
_cell_angle_alpha    	90
_cell_angle_beta    	90
_cell_angle_gamma    	120
_cell_volume    	1535.8(4)
_cell_formula_units_Z    	3
_exptl_crystal_density_diffrn    	3.070
_exptl_crystal_density_meas    	?
_diffrn_radiation_type    	'MoK\a'
_diffrn_radiation_wavelength    	0.71073
_cell_measurement_reflns_used    	40
_cell_measurement_theta_min    	3
_cell_measurement_theta_max    	14
_exptl_absorpt_coefficient_mu    	1.07
_cell_measurement_temperature    	297
_exptl_crystal_description    	'trigonal prism'
_exptl_crystal_size_max    	?
_exptl_crystal_size_mid    	?
_exptl_crystal_size_min    	?
_exptl_crystal_size_rad    	0.24
_exptl_crystal_colour    	'Bright blue'
_chemical_compound_source    	'Paraiba, Brazil'
_diffrn_measurement_device    	'Nicolet R3m'
_diffrn_measurement_method    	'\q-2\q'
_exptl_absorpt_correction_type    	'empirical'
_exptl_absorpt_correction_T_min    	0.711
_exptl_absorpt_correction_T_max    	0.727
_diffrn_reflns_number    	1122
_reflns_number_total    	1122
_reflns_number_observed    	1114
_reflns_observed_criterion    	I>2.5\sI
_diffrn_reflns_av_R_equivalents    	?
_diffrn_reflns_theta_max    	30
_diffrn_reflns_limit_h_min    	0
_diffrn_reflns_limit_h_max    	19
_diffrn_reflns_limit_k_min    	0
_diffrn_reflns_limit_k_max    	19
_diffrn_reflns_limit_l_min    	-11
_diffrn_reflns_limit_l_max    	11
_diffrn_standards_number    	2
_diffrn_standards_interval_count    	48
_diffrn_standards_interval_time    	?
_diffrn_standards_decay_%    	1.5
_refine_ls_structure_factor_coef    	F
_refine_ls_R_factor_obs    	0.022
_refine_ls_wR_factor_obs    	0.025
_refine_ls_goodness_of_fit_obs    	1.2
_refine_ls_number_reflns    	1114
_refine_ls_number_parameters    	92
_refine_ls_hydrogen_treatment    	'noref'
_refine_ls_weighting_scheme    	'w = 1/[\s^2^(F) + 0.00061F^2^]'
_refine_ls_shift/esd_max    	0.04
_refine_diff_density_max    	0.18
_refine_diff_density_min    	-0.20
_refine_ls_extinction_method    	'isotropic (empirical)'
_refine_ls_extinction_coef    	
;0.0015(2),  form given in SHELXTL/PC User's Manual (Sheldrick, 1990)
;
_atom_type_scat_source    	'Cromer & Mann (1968)'
loop_
    _atom_site_label
    _atom_site_fract_x
    _atom_site_fract_y
    _atom_site_fract_z
    _atom_site_U_iso_or_equiv
    Na .0 .0 .8408 .0274(9)
    Li .06155(4) .93845(4) .4396(4) .0060(3)
    Al .26003(4) .29690(3) .4643(4) .0052(2)
    Si .18989(3) .19191(3) .0736(4) .0056(2)
    B .89061(9) .10939(9) .6187(5) .0068(7)
    O1 .0 .0 .2946(7) .0288(1)
    O2 .93945(7) .06055(7) .5838(5) .0136(5)
    O3 .13203(8) .86797(8) .5666(5) .0135(5)
    O4 .90603(7) .09397(7) .0009(5) .0097(5)
    O5 .09363(7) .90637(7) -.0231(5) .0103(5)
    O6 .1846(1) .1954(1) .2993(5) .0088(4)
    O7 .28637(8) .2865(1) -.0045(4) .0072(4)
    O8 .2699(1) .2094(1) .6348(4) .0082(4)