Artigo Acesso aberto

The Crystal Structure of Quartz

1922; American Institute of Physics; Volume: 19; Issue: 4 Linguagem: Inglês

10.1103/physrev.19.363

ISSN

1536-6065

Autores

Maurice L. Huggins,

Tópico(s)

X-ray Diffraction in Crystallography

Resumo

The Structure of Quartz (Si${O}_{2}$).---By means of the Lewis theory, a structure has been obtained for quartz which accounts in a satisfactory way for the crystalline form, crystal symmetry, optical rotation, hardness, high melting point, insolubility, and x-ray spectra of the substance. It is in strict accord with the conclusions of W. H. Bragg in regard to the structure. Furthermore, the distance between adjacent silicon and oxygen atoms, calculated from the dimensions of the lattice, as obtained by Bragg, is approximately equal to the sum of their atomic radii, obtained from other crystals.The Arrangement of Atoms and Electrons.---Each silicon atom is surrounded by four pairs of electrons at tetrahedron corners, which act as bonds connecting it to four equidistant oxygen atoms. Each oxygen atom is also surrounded by four tetrahedrally oriented electronpairs, two of which serve as bonds connecting the oxygen to silicon atoms. The crystal is thus not made up of Si${O}_{2}$ units, but is a single molecule, for all of the bonds around each silicon or each oxygen atom are of the same type---the usual type of bond which connects the atoms in a molecule.

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