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Figure 2.18 Structure of crystalline ZrSiO 4 showing the Zr bond ing to SiO 2
units. Zr–O bonding also exists in and out of the plane of the page (not shown).
After ref [15].
shorter than the Zr–O bond length within a chain, as is represented in the figure. Figure
20 show that each Zr atom also shares bonds with other O atoms in neighboring chains,
providing a three-dimensional stability to the material. It is important to note that each Zr
and Si atom has only O atoms as nearest neighbors. Chemical analysis of homogeneous
silicate films is therefore expected to show only Zr–O nearest neighbor bonding, with a
slight effect from Si as a next- nearest neighbor. It is reasonable to assume that for Hf and
Zr concentrations less than that of the stoichiometric MO 2 – SiO 2 compound, nearly all
bonds will be Zr–O (or Hf–O) and Si–O bonds40-42
40