# Supplementary Information (SI) for ChemComm.
# This journal is © The Royal Society of Chemistry 2026

####################################################################### 
# 
# This file contains crystal structure data downloaded from the 
# Cambridge Structural Database (CSD) hosted by the Cambridge 
# Crystallographic Data Centre (CCDC).
# 
# Full information about CCDC data access policies and citation 
# guidelines are available at http://www.ccdc.cam.ac.uk/access/V1 
# 
# Audit and citation data items may have been added by the CCDC. 
# Please retain this information to preserve the provenance of 
# this file and to allow appropriate attribution of the data. 
# 
#######################################################################

data_b2o3-p212121-01
_database_code_depnum_ccdc_archive 'CCDC 2523450'
loop_
_audit_author_name
_audit_author_address
'Dominik Spahr'
;Goethe University Frankfurt
Germany
;
_audit_update_record             
;
2026-01-16 deposited with the CCDC.	2026-02-26 downloaded from the CCDC.
;
_audit_creation_date             2025-12-29
_audit_creation_method           
;
Olex2 1.5
(compiled 2024.02.16 svn.r378c4104 for OlexSys, GUI svn.r6928)
;
_shelx_SHELXL_version_number     2016/6
_chemical_name_common            ?
_chemical_name_systematic        'boron trioxide'
_chemical_formula_moiety         'B2 O3'
_chemical_formula_sum            'B2 O3'
_chemical_formula_weight         69.62
_chemical_absolute_configuration ?
_chemical_melting_point          ?
_chemical_oxdiff_formula         'B2 O3'
loop_
_atom_type_symbol
_atom_type_description
_atom_type_scat_dispersion_real
_atom_type_scat_dispersion_imag
_atom_type_scat_source
B B -0.0005 0.0001 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
O O -0.0011 0.0008 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'

_shelx_space_group_comment       
;
The symmetry employed for this shelxl refinement is uniquely defined
by the following loop, which should always be used as a source of
symmetry information in preference to the above space-group names.
They are only intended as comments.
;
_space_group_crystal_system      orthorhombic
_space_group_IT_number           19
_space_group_name_H-M_alt        'P 21 21 21'
_space_group_name_Hall           'P 2ac 2ab'
loop_
_space_group_symop_operation_xyz
'x, y, z'
'-x+1/2, -y, z+1/2'
'-x, y+1/2, -z+1/2'
'x+1/2, -y+1/2, -z'

_cell_length_a                   4.1372(4)
_cell_length_b                   7.3511(14)
_cell_length_c                   3.9417(6)
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_volume                     119.88(3)
_cell_formula_units_Z            4
_cell_measurement_reflns_used    195
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      15.4140
_cell_measurement_theta_min      2.3390
_shelx_estimated_absorpt_T_max   ?
_shelx_estimated_absorpt_T_min   ?
_exptl_absorpt_coefficient_mu    0.085
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.49899
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   
;
CrysAlisPro 1.171.43.67a (Rigaku Oxford Diffraction, 2023)
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_absorpt_special_details   ?
_exptl_crystal_colour            colourless
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    3.857
_exptl_crystal_density_meas      ?
_exptl_crystal_density_method    ?
_exptl_crystal_description       irregular
_exptl_crystal_F_000             136
_exptl_crystal_preparation       'high-pressure high-temperature synthesis'
_exptl_crystal_size_max          0.001
_exptl_crystal_size_mid          0.001
_exptl_crystal_size_min          0.001
_exptl_transmission_factor_max   ?
_exptl_transmission_factor_min   ?
_diffrn_reflns_av_R_equivalents  0.0075
_diffrn_reflns_av_unetI/netI     0.0140
_diffrn_reflns_Laue_measured_fraction_full 0.699
_diffrn_reflns_Laue_measured_fraction_max 0.441
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       6
_diffrn_reflns_limit_l_min       -6
_diffrn_reflns_number            445
_diffrn_reflns_point_group_measured_fraction_full 0.679
_diffrn_reflns_point_group_measured_fraction_max 0.381
_diffrn_reflns_theta_full        9.831
_diffrn_reflns_theta_max         15.478
_diffrn_reflns_theta_min         2.262
_diffrn_ambient_temperature      293(2)
_diffrn_ambient_pressure         50000000
_diffrn_detector                 'Hybrid Photon Counting'
_diffrn_detector_area_resol_mean 13
_diffrn_detector_type            'Eiger2 X 4M CdTe'
_diffrn_measured_fraction_theta_full 0.699
_diffrn_measured_fraction_theta_max 0.441
_diffrn_measurement_details      
;
List of Runs (angles in degrees, time in seconds):

  # Type    Start    End  Width  tₑₓₚ   ω     θ     κ     φ   Frames
#--------------------------------------------------------------------------
  1  ω    -33.00  33.50   0.50    1.00    --    0.00   0.00   0.00  133
;
_diffrn_measurement_device       'abstract diffractometer'
_diffrn_measurement_device_type  
'esperanto-CrysAlisPro-abstract goniometer imported esperanto images'
_diffrn_measurement_method       'ω scans'
_diffrn_orient_matrix_axis[1]    matrixX
_diffrn_orient_matrix_axis[2]    matrixY
_diffrn_orient_matrix_axis[3]    matrixZ
_diffrn_orient_matrix_type       
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      -0.0229040000
_diffrn_orient_matrix_UB_12      -0.0284899000
_diffrn_orient_matrix_UB_13      -0.0435405000
_diffrn_orient_matrix_UB_21      0.0447718000
_diffrn_orient_matrix_UB_22      -0.0244462000
_diffrn_orient_matrix_UB_23      0.0297378000
_diffrn_orient_matrix_UB_31      -0.0466839000
_diffrn_orient_matrix_UB_32      -0.0098282000
_diffrn_orient_matrix_UB_33      0.0493221000
_diffrn_radiation_monochromator  synchrotron
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           synchrotron
_diffrn_radiation_wavelength     0.28457
_diffrn_source                   synchrotron
_diffrn_source_type              'ESRF, Beamline ID11'
_reflns_Friedel_coverage         0.403
_reflns_Friedel_fraction_full    0.638
_reflns_Friedel_fraction_max     0.284
_reflns_number_gt                286
_reflns_number_total             317
_reflns_special_details          
;
 Reflections were merged by SHELXL according to the crystal
 class for the calculation of statistics and refinement.
 
 _reflns_Friedel_fraction is defined as the number of unique
 Friedel pairs measured divided by the number that would be
 possible theoretically, ignoring centric projections and
 systematic absences.
;
_reflns_threshold_expression     'I > 2σ(I)'
_computing_cell_refinement       'CrysAlisPro 1.171.43.67a (Rigaku OD, 2023)'
_computing_data_collection       
'CrysAlisPro 1.171.43.67a (Rigaku OD, 2023) (IMPORT)'
_computing_data_reduction        'CrysAlisPro 1.171.43.67a (Rigaku OD, 2023)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2016/6 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT 2014/5 (Sheldrick, 2014)'
_refine_diff_density_max         0.497
_refine_diff_density_min         -0.445
_refine_diff_density_rms         0.135
_refine_ls_abs_structure_details 
;
 Flack x determined using 80 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -1.1(10)
_refine_ls_extinction_coef       .
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.133
_refine_ls_hydrogen_treatment    undef
_refine_ls_matrix_type           full
_refine_ls_number_parameters     46
_refine_ls_number_reflns         317
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.0418
_refine_ls_R_factor_gt           0.0370
_refine_ls_restrained_S_all      1.133
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details     
'w=1/[σ²(Fo²)+(0.0617P)²] where P=(Fo²+2Fc²)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0871
_refine_ls_wR_factor_ref         0.0903
_refine_special_details          ?
_olex2_refinement_description    
;
;
_atom_sites_solution_hydrogens   .
_atom_sites_solution_primary     dual
_atom_sites_solution_secondary   ?
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
_atom_site_adp_type
_atom_site_occupancy
_atom_site_site_symmetry_order
_atom_site_calc_flag
_atom_site_refinement_flags_posn
_atom_site_refinement_flags_adp
_atom_site_refinement_flags_occupancy
_atom_site_disorder_assembly
_atom_site_disorder_group
O3 O 0.9118(3) 0.66534(18) 0.0029(4) 0.0062(3) Uani 1 1 d . . . . .
O2 O 0.5665(3) 0.65453(19) 0.4626(4) 0.0066(3) Uani 1 1 d . . . . .
O1 O 0.4028(3) 0.5210(2) 0.9596(4) 0.0060(3) Uani 1 1 d . . . . .
B2 B 0.5771(5) 0.6721(3) 0.1199(5) 0.0068(4) Uani 1 1 d . . . . .
B1 B 0.4230(5) 0.5046(3) 0.5927(6) 0.0068(4) Uani 1 1 d . . . . .


_geom_special_details            
;
 All esds (except the esd in the dihedral angle between two l.s. planes)
 are estimated using the full covariance matrix.  The cell esds are taken
 into account individually in the estimation of esds in distances, angles
 and torsion angles; correlations between esds in cell parameters are only
 used when they are defined by crystal symmetry.  An approximate (isotropic)
 treatment of cell esds is used for estimating esds involving l.s. planes.
;
loop_
_geom_bond_atom_site_label_1
_geom_bond_atom_site_label_2
_geom_bond_distance
_geom_bond_site_symmetry_2
_geom_bond_publ_flag
O3 B2 1.459(3) 4_565 ?
O3 B2 1.460(3) . ?
O3 B1 1.467(3) 2_664 ?
O2 B2 1.358(3) . ?
O2 B1 1.353(3) . ?
O1 B2 1.468(3) 1_556 ?
O1 B1 1.458(3) 2_565 ?
O1 B1 1.453(3) . ?

loop_
_geom_angle_atom_site_label_1
_geom_angle_atom_site_label_2
_geom_angle_atom_site_label_3
_geom_angle
_geom_angle_site_symmetry_1
_geom_angle_site_symmetry_3
_geom_angle_publ_flag
B2 O3 B2 121.41(14) 4_565 . ?
B2 O3 B1 113.24(17) . 2_664 ?
B2 O3 B1 123.98(19) 4_565 2_664 ?
B1 O2 B2 117.98(18) . . ?
B1 O1 B2 113.38(16) 2_565 1_556 ?
B1 O1 B2 117.56(17) . 1_556 ?
B1 O1 B1 113.61(13) . 2_565 ?
O3 B2 O3 111.57(18) 4_465 . ?
O3 B2 O1 104.28(16) 4_465 1_554 ?
O3 B2 O1 107.71(16) . 1_554 ?
O2 B2 O3 109.98(17) . . ?
O2 B2 O3 113.14(17) . 4_465 ?
O2 B2 O1 109.89(19) . 1_554 ?
O2 B1 O3 113.45(17) . 2_665 ?
O2 B1 O1 111.97(19) . 2_564 ?
O2 B1 O1 109.58(18) . . ?
O1 B1 O3 103.52(17) 2_564 2_665 ?
O1 B1 O3 109.71(17) . 2_665 ?
O1 B1 O1 108.39(14) . 2_564 ?

loop_
_geom_torsion_atom_site_label_1
_geom_torsion_atom_site_label_2
_geom_torsion_atom_site_label_3
_geom_torsion_atom_site_label_4
_geom_torsion
_geom_torsion_site_symmetry_1
_geom_torsion_site_symmetry_2
_geom_torsion_site_symmetry_3
_geom_torsion_site_symmetry_4
_geom_torsion_publ_flag
B2 O3 B2 O3 18.58(15) 4_565 . . 4_465 ?
B2 O3 B2 O2 -107.8(2) 4_565 . . . ?
B2 O3 B2 O1 132.45(19) 4_565 . . 1_554 ?
B2 O2 B1 O3 63.6(2) . . . 2_665 ?
B2 O2 B1 O1 -173.45(16) . . . . ?
B2 O2 B1 O1 -53.2(2) . . . 2_564 ?
B2 O1 B1 O3 115.82(19) 1_556 . . 2_665 ?
B2 O1 B1 O2 -9.3(2) 1_556 . . . ?
B2 O1 B1 O1 -131.79(19) 1_556 . . 2_564 ?
B1 O3 B2 O3 -174.30(16) 2_664 . . 4_465 ?
B1 O3 B2 O2 59.3(2) 2_664 . . . ?
B1 O3 B2 O1 -60.4(2) 2_664 . . 1_554 ?
B1 O2 B2 O3 119.7(2) . . . 4_465 ?
B1 O2 B2 O3 -114.8(2) . . . . ?
B1 O2 B2 O1 3.6(2) . . . 1_554 ?
B1 O1 B1 O3 -108.40(19) 2_565 . . 2_665 ?
B1 O1 B1 O2 126.4(2) 2_565 . . . ?
B1 O1 B1 O1 3.98(9) 2_565 . . 2_564 ?

loop_
_axis.id
_axis.system
_axis.type
_axis.equipment
_axis.parity
_axis.depends_on
_axis.zero
_axis.vector[1]
_axis.vector[2]
_axis.vector[3]
source abstract . source . . . 1.00000000 0.00000000 0.00000000
omega abstract rotation goniometer -1 . 0.00000000 0.00000000 0.00000000
1.00000000
kappa abstract rotation goniometer -1 omega 0.00000000 -0.76604444 0.00000000
0.64278761
phi abstract rotation goniometer -1 kappa . 0.00000000 0.00000000 1.00000000
theta abstract rotation goniometer -1 . -0.26362000 0.00000000 0.00000000
1.00000000
matrixX abstract general general . phi . 1.00000000 0.00000000 0.00000000
matrixY abstract general general . phi . 0.00000000 1.00000000 0.00000000
matrixZ abstract general general . phi . 0.00000000 0.00000000 1.00000000
dacX abstract translation general . phi . 0.00000000 1.00000000 0.00000000
dacY abstract translation general . phi . -1.00000000 0.00000000 0.00000000
dacZ abstract translation general . phi . 0.00000000 0.00000000 1.00000000

_olex2_submission_special_instructions 'No special instructions were received'
_oxdiff_exptl_absorpt_empirical_details 
;
Empirical correction (ABSPACK) includes:
- Absorption correction using spherical harmonics
- Frame scaling
- Detector area scaling
;
_oxdiff_exptl_absorpt_empirical_full_max 1.595
_oxdiff_exptl_absorpt_empirical_full_min 0.848


# start Validation Reply Form
_vrf_PLAT029_b2o3-p212121-01     
;
PROBLEM: _diffrn_measured_fraction_theta_full value Low .      0.699 Why?  
RESPONSE: The dataset was incomplete since the data were collected in
 a diamond anvil cell metallic body of which shadows
 more than 60% of the reflections.
;
_vrf_PLAT089_b2o3-p212121-01     
;
PROBLEM: Poor Data / Parameter Ratio (Zmax <= 18) .......       4.91 Note  
RESPONSE: The dataset was incomplete since the data were collected in
 a diamond anvil cell metallic body of which shadows
 more than 60% of the reflections.
;
_vrf_PLAT911_b2o3-p212121-01     
;
PROBLEM: Missing FCF Refl Between Thmin & STh/L=    0.600         42 Report
RESPONSE: The dataset was incomplete since the data were collected in
 a diamond anvil cell metallic body of which shadows
 more than 60% of the reflections.
;
_vrf_PLAT915_b2o3-p212121-01     
;
PROBLEM: No Flack x Check Done: Low Friedel Pair Coverage         29 %     
RESPONSE: The dataset was incomplete since the data were collected in
 a diamond anvil cell metallic body of which shadows
 more than 60% of the reflections.
;
# end Validation Reply Form
