data_Ca4P2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.96
_cell_length_b   11.86
_cell_length_c   9.39
_cell_angle_alpha   90.0
_cell_angle_beta   90.9
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca4P2O9
_chemical_formula_sum   'Ca16 P8 O36'
_cell_volume   775.42
_cell_formula_units_Z   4
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Ca  Ca0  1  0.73  0.94  0.12  1.0
  Ca  Ca1  1  0.25  0.47  0.96  1.0
  Ca  Ca2  1  0.72  1.0  1.0  1.0
  Ca  Ca3  1  0.83  0.55  0.36  1.0
  Ca  Ca4  1  0.12  0.3  0.37  1.0
  Ca  Ca5  1  0.04  0.74  0.42  1.0
  Ca  Ca6  1  0.33  0.55  0.86  1.0
  Ca  Ca7  1  0.54  0.53  0.38  1.0
  Ca  Ca8  1  0.27  0.6  0.0  1.0
  Ca  Ca9  1  0.49  0.62  0.53  1.0
  Ca  Ca10  1  0.78  0.81  0.97  1.0
  Ca  Ca11  1  0.7  0.22  0.02  1.0
  Ca  Ca12  1  0.98  0.48  0.03  1.0
  Ca  Ca13  1  0.1  0.07  0.39  1.0
  Ca  Ca14  1  0.56  0.54  0.43  1.0
  Ca  Ca15  1  0.08  0.87  0.27  1.0
  P  P52  1  0.64  0.84  0.85  1.0
  P  P53  1  0.31  0.64  0.02  1.0
  P  P54  1  0.6  0.49  1.0  1.0
  P  P55  1  0.89  0.79  0.53  1.0
  P  P56  1  0.93  0.86  0.86  1.0
  P  P57  1  0.22  0.42  0.39  1.0
  P  P58  1  0.5  0.57  0.37  1.0
  P  P59  1  0.17  0.91  0.54  1.0
  O  O16  1  0.08  0.26  0.01  1.0
  O  O17  1  0.4  0.32  0.08  1.0
  O  O18  1  0.84  0.11  0.15  1.0
  O  O19  1  0.37  0.28  0.52  1.0
  O  O20  1  0.12  0.14  0.53  1.0
  O  O21  1  0.98  0.89  0.02  1.0
  O  O22  1  0.04  0.18  0.11  1.0
  O  O23  1  0.68  0.05  0.14  1.0
  O  O24  1  0.91  0.8  0.34  1.0
  O  O25  1  0.49  0.4  0.46  1.0
  O  O26  1  0.22  0.81  0.72  1.0
  O  O27  1  0.62  0.35  0.79  1.0
  O  O28  1  0.89  0.31  0.9  1.0
  O  O29  1  0.71  0.8  0.22  1.0
  O  O30  1  0.26  0.05  0.53  1.0
  O  O31  1  0.4  0.05  0.47  1.0
  O  O32  1  0.22  0.55  0.52  1.0
  O  O33  1  0.28  0.51  0.58  1.0
  O  O34  1  0.54  0.44  0.81  1.0
  O  O35  1  0.6  0.48  0.87  1.0
  O  O36  1  0.41  0.98  0.92  1.0
  O  O37  1  0.56  0.12  0.86  1.0
  O  O38  1  0.11  0.87  0.17  1.0
  O  O39  1  0.92  0.24  0.49  1.0
  O  O40  1  0.19  0.28  0.6  1.0
  O  O41  1  0.6  0.73  0.67  1.0
  O  O42  1  0.33  0.33  0.93  1.0
  O  O43  1  0.9  0.87  0.05  1.0
  O  O44  1  0.13  0.12  0.25  1.0
  O  O45  1  0.78  0.25  0.28  1.0
  O  O46  1  0.83  0.82  0.37  1.0
  O  O47  1  0.7  0.21  0.86  1.0
  O  O48  1  0.44  0.21  0.87  1.0
  O  O49  1  0.98  0.04  0.24  1.0
  O  O50  1  0.41  0.25  0.31  1.0
  O  O51  1  0.74  0.19  0.38  1.0

data_Ca4P2O9
_symmetry_space_group_name_H-M   P1
_cell_length_a   6.96
_cell_length_b   9.39
_cell_length_c   11.86
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.9
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca4P2O9
_chemical_formula_sum   'Ca16 P8 O36'
_cell_volume   775.42
_cell_formula_units_Z   4
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Ca  Ca0  1  0.02  0.97  0.52  1.0
  Ca  Ca1  1  0.17  0.64  0.45  1.0
  Ca  Ca2  1  0.22  0.03  0.19  1.0
  Ca  Ca3  1  0.27  0.88  0.06  1.0
  Ca  Ca4  1  0.28  0.0  0.0  1.0
  Ca  Ca5  1  0.3  0.98  0.78  1.0
  Ca  Ca6  1  0.44  0.57  0.46  1.0
  Ca  Ca7  1  0.46  0.62  0.47  1.0
  Ca  Ca8  1  0.51  0.47  0.38  1.0
  Ca  Ca9  1  0.67  0.14  0.45  1.0
  Ca  Ca10  1  0.73  1.0  0.4  1.0
  Ca  Ca11  1  0.75  0.04  0.53  1.0
  Ca  Ca12  1  0.88  0.63  0.7  1.0
  Ca  Ca13  1  0.9  0.61  0.93  1.0
  Ca  Ca14  1  0.92  0.73  0.13  1.0
  Ca  Ca15  1  0.96  0.58  0.26  1.0
  P  P16  1  0.07  0.14  0.14  1.0
  P  P17  1  0.11  0.47  0.21  1.0
  P  P18  1  0.36  0.15  0.16  1.0
  P  P19  1  0.4  0.0  0.51  1.0
  P  P20  1  0.5  0.63  0.43  1.0
  P  P21  1  0.69  0.98  0.36  1.0
  P  P22  1  0.78  0.61  0.58  1.0
  P  P23  1  0.83  0.46  0.09  1.0
  O  O24  1  0.02  0.98  0.11  1.0
  O  O25  1  0.02  0.76  0.96  1.0
  O  O26  1  0.08  0.51  0.76  1.0
  O  O27  1  0.09  0.66  0.2  1.0
  O  O28  1  0.1  0.95  0.13  1.0
  O  O29  1  0.11  0.1  0.69  1.0
  O  O30  1  0.16  0.85  0.89  1.0
  O  O31  1  0.17  0.63  0.18  1.0
  O  O32  1  0.22  0.72  0.75  1.0
  O  O33  1  0.26  0.62  0.81  1.0
  O  O34  1  0.29  0.78  0.2  1.0
  O  O35  1  0.3  0.14  0.79  1.0
  O  O36  1  0.32  0.86  0.95  1.0
  O  O37  1  0.38  0.21  0.65  1.0
  O  O38  1  0.4  0.13  0.52  1.0
  O  O39  1  0.4  0.33  0.27  1.0
  O  O40  1  0.44  0.14  0.88  1.0
  O  O41  1  0.46  0.19  0.56  1.0
  O  O42  1  0.51  0.54  0.6  1.0
  O  O43  1  0.56  0.13  0.79  1.0
  O  O44  1  0.59  0.69  0.75  1.0
  O  O45  1  0.59  0.08  0.02  1.0
  O  O46  1  0.6  0.53  0.95  1.0
  O  O47  1  0.6  0.92  0.68  1.0
  O  O48  1  0.63  0.48  0.72  1.0
  O  O49  1  0.67  0.07  0.67  1.0
  O  O50  1  0.72  0.42  0.49  1.0
  O  O51  1  0.74  0.47  0.95  1.0
  O  O52  1  0.78  0.28  0.19  1.0
  O  O53  1  0.78  0.48  0.45  1.0
  O  O54  1  0.81  0.4  0.72  1.0
  O  O55  1  0.87  0.75  0.88  1.0
  O  O56  1  0.88  0.47  0.86  1.0
  O  O57  1  0.89  0.83  0.13  1.0
  O  O58  1  0.92  0.99  0.74  1.0
  O  O59  1  0.96  0.89  0.82  1.0

Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca P P P P P P P P O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca Ca P P P P P P P P O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O 0 2 o o - 0 31 o + o 0 37 o o o 1 6 o o o 1 8 o o + 1 12 - o + 1 50 o o o 2 31 o + + 2 44 o o o 3 14 o o o 3 7 o o o 3 22 o o o 4 47 - o o 4 21 o o o 4 58 o o o 5 32 - o o 5 19 - o o 6 8 o o + 7 22 o o o 7 14 o o o 7 33 o o o 8 17 o o o 8 12 - o o 9 22 o o o 9 14 o o o 9 49 o o o 10 16 o o o 10 20 o o o 10 51 o o + 11 55 o o - 11 36 o o - 12 36 o o - 12 24 + o o 13 57 - o o 13 38 o o o 13 52 o o o 13 28 o o o 14 33 o o o 15 46 o o o 16 44 o o o 16 49 o o o 18 43 o o o 19 54 o o o 19 32 o o o 19 49 o o o 20 51 o o + 20 29 o o + 20 34 + o o 21 40 o o o 21 33 o o o 21 41 o o o 21 58 o o o 23 34 o o o 23 38 o + o 24 30 o o o 24 36 - o - 25 50 o o - 25 58 o o o 26 31 o o o 26 57 o o o 26 30 + o o 27 48 o o o 27 33 o o o 27 58 o o o 28 38 o o o 28 47 - o o 29 51 o o o 30 52 o o o 32 54 o o o 32 37 o o o 33 58 o o o 35 42 o o o 35 36 o o o 36 55 o o o 37 54 o o o 38 39 o o o 40 41 o o o 42 43 o o o 44 45 o + o 45 56 o o o 45 55 o o o 47 59 o o o 50 56 o o o 52 57 - o o 52 58 o o o 53 59 o o o 53 58 o o o 55 56 o o o 58 59 o o o 
Ca4(PO4)2O crystallizes in the triclinic P1 space group. There are sixteen inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 2-coordinate geometry to one O(14), one O(28), one O(34), and one O(8) atom. The Ca(1)-O(14) bond length is 1.94 Å. The Ca(1)-O(28) bond length is 1.62 Å. The Ca(1)-O(34) bond length is 2.32 Å. The Ca(1)-O(8) bond length is 1.30 Å. In the second Ca site, Ca(2) is bonded in a distorted single-bond geometry to one Ca(13), one Ca(7), one O(2), and one O(27) atom. The Ca(2)-Ca(13) bond length is 2.00 Å. The Ca(2)-Ca(7) bond length is 1.39 Å. The Ca(2)-O(2) bond length is 2.35 Å. The Ca(2)-O(27) bond length is 1.78 Å. In the third Ca site, Ca(3) is bonded in a distorted single-bond geometry to one O(21), one O(22), one O(3), and one O(8) atom. The Ca(3)-O(21) bond length is 2.26 Å. The Ca(3)-O(22) bond length is 2.23 Å. The Ca(3)-O(3) bond length is 2.14 Å. The Ca(3)-O(8) bond length is 1.51 Å. In the fourth Ca site, Ca(4) is bonded in a 2-coordinate geometry to one P(6) and one O(17) atom. The Ca(4)-P(6) bond length is 3.10 Å. The Ca(4)-O(17) bond length is 3.05 Å. In the fifth Ca site, Ca(5) is bonded in a 2-coordinate geometry to one P(6), one O(24), one O(25), one O(30), one O(35), one O(4), and one O(7) atom. The Ca(5)-P(6) bond length is 1.62 Å. The Ca(5)-O(24) bond length is 1.89 Å. The Ca(5)-O(25) bond length is 2.23 Å. The Ca(5)-O(30) bond length is 2.58 Å. The Ca(5)-O(35) bond length is 2.18 Å. The Ca(5)-O(4) bond length is 2.23 Å. The Ca(5)-O(7) bond length is 2.86 Å. In the sixth Ca site, Ca(6) is bonded in a 1-coordinate geometry to one P(4), one O(17), and one O(9) atom. The Ca(6)-P(4) bond length is 1.64 Å. The Ca(6)-O(17) bond length is 2.72 Å. The Ca(6)-O(9) bond length is 1.38 Å. In the seventh Ca site, Ca(7) is bonded in a 7-coordinate geometry to one Ca(2), one Ca(9), one P(2), one P(3), one O(18), one O(19), and one O(20) atom. The Ca(7)-Ca(9) bond length is 1.53 Å. The Ca(7)-P(2) bond length is 1.84 Å. The Ca(7)-P(3) bond length is 2.36 Å. The Ca(7)-O(18) bond length is 2.72 Å. The Ca(7)-O(19) bond length is 2.04 Å. The Ca(7)-O(20) bond length is 2.06 Å. In the eighth Ca site, Ca(8) is bonded in a 3-coordinate geometry to one Ca(15), one P(7), and one O(10) atom. The Ca(8)-Ca(15) bond length is 0.48 Å. The Ca(8)-P(7) bond length is 0.56 Å. The Ca(8)-O(10) bond length is 1.67 Å. In the ninth Ca site, Ca(9) is bonded in a single-bond geometry to one Ca(7) and one P(2) atom. The Ca(9)-P(2) bond length is 0.56 Å. In the tenth Ca site, Ca(10) is bonded in a 5-coordinate geometry to one Ca(15), one P(7), one O(17), one O(18), and one O(26) atom. The Ca(10)-Ca(15) bond length is 1.39 Å. The Ca(10)-P(7) bond length is 1.63 Å. The Ca(10)-O(17) bond length is 2.06 Å. The Ca(10)-O(18) bond length is 2.04 Å. The Ca(10)-O(26) bond length is 2.05 Å. In the eleventh Ca site, Ca(11) is bonded in a 4-coordinate geometry to one P(1), one P(5), one O(14), and one O(28) atom. The Ca(11)-P(1) bond length is 1.53 Å. The Ca(11)-P(5) bond length is 1.64 Å. The Ca(11)-O(14) bond length is 2.35 Å. The Ca(11)-O(28) bond length is 1.38 Å. In the twelfth Ca site, Ca(12) is bonded in a 1-coordinate geometry to one O(13), one O(2), one O(22), one O(3), one O(30), one O(32), one O(33), and one O(7) atom. The Ca(12)-O(13) bond length is 2.06 Å. The Ca(12)-O(2) bond length is 2.41 Å. The Ca(12)-O(22) bond length is 2.15 Å. The Ca(12)-O(3) bond length is 2.05 Å. The Ca(12)-O(30) bond length is 2.51 Å. The Ca(12)-O(32) bond length is 1.55 Å. The Ca(12)-O(33) bond length is 2.23 Å. The Ca(12)-O(7) bond length is 2.58 Å. In the thirteenth Ca site, Ca(13) is bonded in a 4-coordinate geometry to one Ca(2), one P(3), one O(1), and one O(13) atom. The Ca(13)-P(3) bond length is 2.70 Å. The Ca(13)-O(1) bond length is 2.59 Å. The Ca(13)-O(13) bond length is 2.36 Å. In the fourteenth Ca site, Ca(14) is bonded in a 4-coordinate geometry to one O(15), one O(29), one O(34), and one O(5) atom. The Ca(14)-O(15) bond length is 1.68 Å. The Ca(14)-O(29) bond length is 1.51 Å. The Ca(14)-O(34) bond length is 1.68 Å. The Ca(14)-O(5) bond length is 1.57 Å. In the fifteenth Ca site, Ca(15) is bonded in a 2-coordinate geometry to one Ca(10), one Ca(8), one P(7), and one O(10) atom. The Ca(15)-P(7) bond length is 0.74 Å. The Ca(15)-O(10) bond length is 1.78 Å. In the sixteenth Ca site, Ca(16) is bonded in a 2-coordinate geometry to one O(23), one O(34), and one O(9) atom. The Ca(16)-O(23) bond length is 0.90 Å. The Ca(16)-O(34) bond length is 2.12 Å. The Ca(16)-O(9) bond length is 1.62 Å. There are eight inequivalent P sites. In the first P site, P(1) is bonded in a 2-coordinate geometry to one Ca(11), one O(21), and one O(26) atom. The P(1)-O(21) bond length is 2.38 Å. The P(1)-O(26) bond length is 2.14 Å. In the second P site, P(2) is bonded in a single-bond geometry to one Ca(7) and one Ca(9) atom. In the third P site, P(3) is bonded in a single-bond geometry to one Ca(13), one Ca(7), one O(2), and one O(20) atom. The P(3)-O(2) bond length is 2.50 Å. The P(3)-O(20) bond length is 1.24 Å. In the fourth P site, P(4) is bonded in a 2-coordinate geometry to one Ca(6) and one O(31) atom. The P(4)-O(31) bond length is 1.59 Å. In the fifth P site, P(5) is bonded in a 2-coordinate geometry to one Ca(11) and one O(6) atom. The P(5)-O(6) bond length is 1.59 Å. In the sixth P site, P(6) is bonded in a 1-coordinate geometry to one Ca(4), one Ca(5), one O(10), one O(17), one O(18), and one O(4) atom. The P(6)-O(10) bond length is 1.97 Å. The P(6)-O(17) bond length is 2.00 Å. The P(6)-O(18) bond length is 2.06 Å. The P(6)-O(4) bond length is 2.23 Å. In the seventh P site, P(7) is bonded in a 2-coordinate geometry to one Ca(10), one Ca(15), and one Ca(8) atom. In the eighth P site, P(8) is bonded in a distorted bent 120 degrees geometry to one O(11) and one O(15) atom. The P(8)-O(11) bond length is 2.14 Å. The P(8)-O(15) bond length is 1.77 Å. There are thirty-six inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Ca(13), one O(13), and one O(7) atom. The O(1)-O(13) bond length is 1.75 Å. The O(1)-O(7) bond length is 1.43 Å. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(12), one Ca(2), one P(3), and one O(27) atom. The O(2)-O(27) bond length is 1.45 Å. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ca(12), one Ca(3), one O(34), one O(7), and one O(8) atom. The O(3)-O(34) bond length is 1.54 Å. The O(3)-O(7) bond length is 1.65 Å. The O(3)-O(8) bond length is 1.31 Å. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Ca(5), one P(6), one O(10), one O(25), and one O(35) atom. The O(4)-O(10) bond length is 1.73 Å. The O(4)-O(25) bond length is 1.48 Å. The O(4)-O(35) bond length is 1.98 Å. In the fifth O site, O(5) is bonded in a single-bond geometry to one Ca(14), one O(15), and one O(25) atom. The O(5)-O(15) bond length is 1.44 Å. The O(5)-O(25) bond length is 1.84 Å. In the sixth O site, O(6) is bonded in a distorted water-like geometry to one P(5) and one O(28) atom. The O(6)-O(28) bond length is 0.64 Å. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Ca(12), one Ca(5), one O(1), one O(29), and one O(3) atom. The O(7)-O(29) bond length is 1.63 Å. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Ca(1), one Ca(3), and one O(3) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Ca(16), one Ca(6), and one O(31) atom. The O(9)-O(31) bond length is 0.64 Å. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Ca(15), one Ca(8), one P(6), and one O(4) atom. In the eleventh O site, O(11) is bonded in a distorted single-bond geometry to one P(8) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one O(19) and one O(32) atom. The O(12)-O(19) bond length is 1.18 Å. The O(12)-O(32) bond length is 1.84 Å. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Ca(12), one Ca(13), one O(1), and one O(32) atom. The O(13)-O(32) bond length is 1.83 Å. In the fourteenth O site, O(14) is bonded in a 1-coordinate geometry to one Ca(1) and one Ca(11) atom. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one Ca(14), one P(8), one O(16), and one O(5) atom. The O(15)-O(16) bond length is 1.18 Å. In the sixteenth O site, O(16) is bonded in a distorted single-bond geometry to one O(15) atom. In the seventeenth O site, O(17) is bonded in a 4-coordinate geometry to one Ca(10), one Ca(4), one Ca(6), one P(6), and one O(18) atom. The O(17)-O(18) bond length is 0.84 Å. In the eighteenth O site, O(18) is bonded in a 4-coordinate geometry to one Ca(10), one Ca(7), one P(6), and one O(17) atom. In the nineteenth O site, O(19) is bonded in a 3-coordinate geometry to one Ca(7), one O(12), and one O(20) atom. The O(19)-O(20) bond length is 0.84 Å. In the twentieth O site, O(20) is bonded in a 1-coordinate geometry to one Ca(7), one P(3), and one O(19) atom. In the twenty-first O site, O(21) is bonded in a 2-coordinate geometry to one Ca(3) and one P(1) atom. In the twenty-second O site, O(22) is bonded in a 4-coordinate geometry to one Ca(12), one Ca(3), one O(32), and one O(33) atom. The O(22)-O(32) bond length is 1.44 Å. The O(22)-O(33) bond length is 1.36 Å. In the twenty-third O site, O(23) is bonded in a single-bond geometry to one Ca(16) atom. In the twenty-fourth O site, O(24) is bonded in a single-bond geometry to one Ca(5) atom. In the twenty-fifth O site, O(25) is bonded in a 3-coordinate geometry to one Ca(5), one O(4), and one O(5) atom. In the twenty-sixth O site, O(26) is bonded in a 2-coordinate geometry to one Ca(10) and one P(1) atom. In the twenty-seventh O site, O(27) is bonded in a distorted single-bond geometry to one Ca(2), one O(2), and one O(33) atom. The O(27)-O(33) bond length is 1.73 Å. In the twenty-eighth O site, O(28) is bonded in a 3-coordinate geometry to one Ca(1), one Ca(11), and one O(6) atom. In the twenty-ninth O site, O(29) is bonded in a distorted single-bond geometry to one Ca(14), one O(34), and one O(7) atom. The O(29)-O(34) bond length is 1.43 Å. In the thirtieth O site, O(30) is bonded in a 3-coordinate geometry to one Ca(12), one Ca(5), and one O(36) atom. The O(30)-O(36) bond length is 1.16 Å. In the thirty-first O site, O(31) is bonded in a distorted water-like geometry to one P(4) and one O(9) atom. In the thirty-second O site, O(32) is bonded in a single-bond geometry to one Ca(12), one O(12), one O(13), one O(22), and one O(33) atom. The O(32)-O(33) bond length is 1.79 Å. In the thirty-third O site, O(33) is bonded in a 4-coordinate geometry to one Ca(12), one O(22), one O(27), and one O(32) atom. In the thirty-fourth O site, O(34) is bonded in a 5-coordinate geometry to one Ca(1), one Ca(14), one Ca(16), one O(29), and one O(3) atom. In the thirty-fifth O site, O(35) is bonded in a single-bond geometry to one Ca(5) and one O(4) atom. In the thirty-sixth O site, O(36) is bonded in a distorted single-bond geometry to one O(30) atom.