Footnotes for Table 18 (continued) 6e) Non-metamict. Averages of a natural (Australia), natural (India) and a synthetic zircon. Note that metamict zircon (i.e., radiation damaged zirconium orthosilicate) is natural zircon containing trace amounts of uranium and thorium which radiate alpha particles and cause radiation damage to the crystal. This natural radiation causes an increase in the porosity of the sample and a decrease in most of the elastic stiffnesses [7601]. Metamict zircons have density vahres that range from 4700 to 3900 kg/m3 [76Gl]. Elastic stiffnesses for metamict zircon are given in references [66R3,7301,74A3,7601]. @ The stoichiometry of Na, Li doped lead barium niobate as given in [88X2] is pbo.3~~.533N~,,~.~s~O~ The value given here is believed to be the correct stoichiometry. id The stoichiometry of KNSBN as given in [88X2] is (Ko2uNao&$&3ao&)~O~ The value given here is believed to be the correct stoichiometry. hh) Results of [6OR2] agree within experimental uncertainty with those of [72SlO] for Sn and Sn-OSat% In.