Abstract
The structure and bonding in stishovite, SiO2, is explored with Fourier summation and pseudoatom refinement of merged x-ray single crystal and powder diffraction data. Replacement of the 25 lowest-angle, highly extinction-affected, single crystal reflections with structure factors obtained from low-extinction powder diffraction data has resulted in a significant improvement in the analysis compared with earlier studies. The deformation electron density, total electrostatic potential and total and valence electron densities are mapped. Accumulations of electron density are observed in both SiO bonds, together with non-bonding features displayed about the oxygen on both sides of a plane formed by three bonds with Si. Deficits of electron density between O atoms across the shared-edges are rationalized in terms of the Pauli exclusion principle. There is no evidence for strong repulsion of Si atoms across the same ring. The total electrostatic potential has a continuous low value for the vacant channels in the structure along c with localized minima between O atoms on opposite sides of the channel. The sizes of Si and O are related to the electron density and to the electrostatic potential.
Similar content being viewed by others
References
Bader RFW, Beddall PM, Cade PE (1971) Partitioning and characterization of molecular charge distributions. J Am Chem Soc 93:3095–3107
Baur WH (1976) Rutile-type compounds V. Refinement of MnO2 and MgF2. Acta Crystallogr B 32:2200–2204
Baur WH, Khan AA (1971) Rutile-type compounds. IV. SiO2, GeO2 and a comparison with other rutile-type structures. Acta Crystallogr B 27:2133–2139
Becker P (1977) The theoretical models of extinction. Their domain of applicability. Acta Crystallogr A 33:243–249
Becker PJ, Coppens P (1974a) Extinction within the limit of validity of the Darwin transfer equations. I. General formalisms for primary and secondary extinction and their application to spherical crystals. Acta Crystallogr A 30:129–147
Becker PJ, Coppens P (1974b) Extinction within the limit of validity of the Darwin transfer equations. II. Refinement of extinction in spherical crystals of SrF2 and LiF. Acta Crystallogr A 30:148–153
Bragg WL (1937) Atomic structure of minerals. Cornell University Press, Ithaca, New York
Burdett JK, McLarnan TJ (1984) An orbital interpretation of Pauling's rules. Am Mineral 69:601–621
Clementi E (1965) Tables of atomic functions. IBM Journal of Research and Development 9:supplement
Clementi E, Roetti C (1974) Roothaan-Hartree-Fock atomic wave-functions. At Data Nucl Data Tables 14:177–478
Cohen ML (1981) Pseudopotentials and crystal structure. In: O'Keeffe M and Navrotsky A (eds) Structure and bonding in crystals I. Academic Press, London, 25–48
Cromer DT, Liberman D (1970) Relativistic calculations of anomalous scattering factors for X-rays. J Chem Phys 53:1891–1898
Downs JW, Hill RJ, Newton MD, Tossell JA, Gibbs GV (1982) Theoretical and experimental charge distributions in euclase and stishovite. In: Coppens P, Hall MB (eds) Electron distributions and the chemical bond. Plenum Press, New York, pp 173–189
Finger LW, Gibbs GV (1985) A derivation of bonded radii from theoretical molecular charge distributions. EOS, Transactions, American Geophysical Union, 66:356–357
Fink MJ, Haller KJ, West R, Michl J (1984) Tetramesitylcyclodisiloxane: A cyclic siloxane with an unusual structure. J Am Chem Soc 106:822–823
Gibbs GV (1982) Molecules as models for bonding in silicates. Am Mineral 67:421–450
Gonschorek W (1982) X-ray charge density study of rutile (TiO2). Z Kristallogr 160:187–203
Gupta A, Tossell JA (1983) Quantum mechanical studies of distortions and polymerization of borate polyhedra. Am Miner 68:989–995
Hehre WJ, Ditchfield R, Stewart RF, Pople JA (1970) Self-consistent molecular orbital methods. IV. Use of Gaussian expansions of Slater-type orbitals. Extension to second-row molecules. J Chem Phys 52:2769–2773
Hill RJ, Newton MD, Gibbs GV (1983) A crystal chemical study of stishovite. J Solid State Chem 47:185–200
McLean AD, Yoshimine M (1967) Tables of linear molecule wave functions. IBM Journal of Research and Development, supplement of November 1967
O'Keeffe M, Hyde BG (1978a) On Si-O-Si configurations in silicates. Acta Crystallogr B 34:27–32
O'Keeffe M, Hyde BG (1978b) Non-bonded interactions and the crystal chemistry of tetrahedral structures related to the wurtzite type (B4). Acta Crystallogr B 34:3519–3528
O'Keeffe M, Hyde BG (1981) The role of nonbonded forces in crystals. In: O'Keeffe M, Navrotsky A (eds) Structure and bonding in crystals I. Academic Press, London, pp 227–254
O'Keeffe M, Hyde BG (1982) Anion coordination and cation packing in oxides. J Solid State Chem 44:24–31
O'Keeffe M, Gibbs GV (1985) Ab initio MO calculations on cyclodisiloxanes and other Si-X-Si-X rings and the problem of “Silica-w”. J Phys Chem 89:4574–4577
O'Keeffe M, Stuart JA (1983) Bond energies in solid oxides. Inorg Chem 22:177–179
Pauling L (1929) The principles determining the structure of complex ionic crystals. J Am Chem Soc 51:1010–1026
Presisinger A (1962) Structure of stishovite, high-pressure SiO2. Naturwissenschaften 49:345
Price PF, Maslen EN, Mair SL (1978) Electron density studies III. A re-evaluation of the electron distribution in crystalline silicon. Acta Crystallogr A34:183–193
Restori R, Schwarzenbach D (1984) Electron density distribution of rutile, TiO2. Abstract in Acta Crystallogr A40:C-158
Shannon RD, Prewitt CT (1969) Effective ionic radii in oxides and fluorides. Acta Crystallogr B 25:925–946
Shintani H, Sato S, Saito Y (1975) Electron-density distribution in rutile crystals. Acta Crystallogr B 31:1981–1982
Sinclair W, Ringwood AE (1978) Single crystal analysis of the structure of stishovite. Nature 272:714–715
Slater JC (1965) Quantum theory of molecules and solids, Vol. 2. McGraw-Hill, New York
Spackman MA, Maslen EN (1986) Chemical properties from the promolecule. J Phys Chem 90:2020–2027
Spackman MA, Stewart RF (1981) Electrostatic potentials in crystals. In: Politzer P, Truhlar DG (eds) Chemical applications of atomic and molecular electrostatic potentials. Plenum Press, New York, pp 407–425
Spackman MA, Stewart RF (1983) Crystalline electrostatic potentials in some simple mineral systems. Abstract L1, ACA Program and Abstracts, 11, No. 1, March 1983
Spackman MA, Stewart RF (1984) Electrostatic properties from accurate diffraction data. In: Hall SR, Ashida T (eds) Methods and applications in crystallographic computing. Oxford University Press, Oxford, pp 302–320
Spackman MA, Stewart RF, LePage Y (1981) Maps of electrostatic properties from X-ray data for α-SiO2(s) and Al2O3(s). Abstract in Acta Crystallogr Suppl A 37:C-138
Stewart RF (1973) Electron population analysis with generalized x-ray scattering factors: Higher multipoles. J Chem Phys 58:1668–1676
Stewart RF (1976) Electron population analysis with rigid pseudoatoms. Acta Crystallogr A 32:565–574
Stewart RF (1979) On the mapping of electrostatic properties from Bragg diffraction data. Chem Phys Lett 65:335–342
Stewart RF (1980) Partitioning of Hartree-Fock atomic form factors into core and valence shells. In: Becker P (ed) Electron and magnetization densities in molecules and crystals. Plenum Press, New York, pp 427–431
Stewart RF, Spackman MA (1981) Charge density distributions. In: O'Keeffe M, Navrotsky A (eds) Structure and bonding in crystals I. Academic Press, London, pp 279–298
Stishov SM, Belov NV (1962) The crystal structure of a new dense modification of silica SiO2. Dokl Akad Nauk SSSR 143:951–954
Swaminathan S, Craven BM, Spackman MA, Stewart RF (1984) Theoretical and experimental studies of the charge density in urea. Acta Crystallogr B 40:398–404
Tossell JA, Gibbs GV (1978) The use of molecular-orbital calculations on model systems for the prediction of bridging-bond-angle variations in siloxanes, silicates, silicon nitrides and silicon sulfides. Acta Crystallogr A 34:463–472
Vegard L (1916) Results of crystal analysis. Phil Mag 32:65–96
Vidal JP, Vidal-Valat G, Galtier M, Kurki-Suonio K (1981) X-ray study of the charge distribution in MgF2. Acta Crystallogr A 37:826–837
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Spackman, M.A., Hill, R.J. & Gibbs, G.V. Exploration of structure and bonding in stishovite with fourier and pseudoatom refinement methods using single crystal and powder X-ray diffraction data. Phys Chem Minerals 14, 139–150 (1987). https://doi.org/10.1007/BF00308217
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00308217