Page 163 - Materials Chemistry, Second Edition

150 2 Solid-State Chemistry

35
For a comprehensive review of recent HTS wire installation projects, and DoE goals related to HTS-
based electrical applications, see: http://www.energetics.com/supercon07/agenda.html
36
Note: there are precedents for crystals with five-fold rotation axes. These crystals are known as
quasicrystals, since they exhibit long-range orientational order but are not consistent with lattice
translations. For example, see: Shechtman, D.; Blech, I.; Gratias, D.; Cahn, J. W. Phys. Rev. Lett.
1984, 53, 1951. Another nice online summary of quasicrystals is: http://www.tau.ac.il/~ronlif/quasi-
crystals.html.
37
Note: the d notation indicates a diamond glide plane, found in diamond or zinc blende extended crystal
structures. Whereas glide planes are found in many inorganic-based crystals, screw axes are found
predominantly in protein structures.
38
Note: scattering from the nucleus does not contribute to coherent scattering due to its relatively large
mass, precluding its oscillation from the impinging of incident X-rays.
39
Note: the cosine of angle f is simply the x component of a unit vector after it is rotated by f around a
unit circle. If the vector is rotated at some constant speed, then its x-value will trace out a cosine wave
as a function of time, with amplitude of vector length. Waves of different wavelengths or periods
would result in the vectors rotating at different speeds; however, X-ray crystallography uses mono-
chromatic photons of a single wavelength.
40
An excellent summary of crystallography and systematic absences is given by: http://xrayweb.chem.
ou.edu/notes/symmetry.html#absence
41
(a) http://shelx.uni-ac.gwdg.de/tutorial/english/shelxs.htm; (b) http://www.lks.physik.uni-erlangen.
de/diffraction/
42
Note: another way to state this is that for a single crystal, only a few lattice planes will be oriented at
their Bragg angle at any one time.
43
(a) Yasuda, K.; Ohta, M. J. Dental Res. 1982, 61, 473. (b) Uzuka, T.; Kanzawa, Y.; Yasuda, K. J. Dent.
Res. 1981, 60, 883.
44
For instance, see: Mukoseev, A. G.; Shabashov, V. A.; Pilugin, V. P.; Sagaradze, V. V. Nanostruct.
Mater. 1998, 10, 273.
45
For example, see: http://xrayweb.chem.ou.edu/notes/twin.html
46
For example, see: Lakes, R. S. Science 1987, 235, 1038.
47
http://www.ntcresearch.org/pdf-rpts/Bref0606/M04-GT21-06e.pdf
48
The yield point for metals with gradual elastic–plastic transitions is constructed by drawing a straight
line parallel to the elastic portion of the stress vs. strain curve at a specific strain offset, usually 0.002.
The intersection of that line and the stress vs. strain curve gives rise to the yield strength, s y , of the
material.
49
Garlick, G. D.; Kamb, W. B. J. Geol. Educ. 1991, 39, 398.
50
For example, see: Fritsch, E.; Massi, L.; Rossman, G. R.; Hainschwang, T.; Jobic, S.; Dessapt, R.,
found online at: http://www.aigsthailand.com/(A(vlNwUMqNyQEkAAAAMzQ3Mjc5MzItNDR-
kYy00NjIzLWEyY2YtNTg3YWM4M2EyYjlj2Mm3M88VUzWx_4m4U5KodgkCri41))/FieldTrips-
Detail.aspx?tID¼185&type¼Publications&AspxAutoDetectCookieSupport¼1
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Note: for a thorough treatment of crystal field theory, see Cotton, F. A.. Wilkinson, G.; Murillo, C. A.;
Bochmann, M. Advanced Inorganic Chemistry, 6th ed., Wiley: New York, 1999.
52 3þ 4 4 4 4
Note: the ground-state atomic term symbol for Cr is F, which splits into T 2 , T 1 and A 2 for an
octahedral transition metal complex. For more information regarding term symbol notation and
absorption spectra for transition metal complexes, see: Shriver et al. Inorganic Chemistry, 4th ed.,
W. H. Freeman: New York, 2006. http://www.scribd.com/doc/6672586/Electronic-Spectroscopy-1
53
Note: excited electrons give off their energy via infrared emission and thermal interactions with the
corundum crystal lattice, referred to as electron–phonon (lattice vibrations) interactions.
54
For an explanation of the electronic transitions underlying ruby lasers, as well as tunable lasers such as
alexandrite, Ti:sapphire, and Nd:YAG, see: Thyagarajan, K. Lasers, Theory and Applications, Plenum
Press: New York, 1981.