431 



TABLE 450.— DIELECTRIC CONSTANT OF CRYSTALS (concluded) 



Name Composition ATa 



Tartrates : 



Rochelle salt NaKGH 4 O -4H 2 O 8.0 



" 30°C§.. ... 300 



NaNH<GH<Cv4H 2 9.0 



LiKGH<CvH 2 5.84 



LiNH 4 GH 4 CvH 2 7.2 



Monoclinic crystals 



Lithium sulfate Li 2 S0 4 -H 2 5.6 



Tartaric acid GH«0« 4.3 



Potassium tartrate KjCJLCVir^O 6.44 



Ammonium tartrate . . . (NH«) 2 GH«06 6.45 

 Ethylene diamine 



tartrate (EDT) GN 2 H 8 -GH 6 6 5.0 



§ See also figure 16. 



8.22 6.0 



free 



References: a, Bechmann, R., and Lynch, A. C, Nature, vol. 163, p. 91S, 1949. b, Cady, W. G., 



Piezoelectricity, McGraw-Hill, New York, 1946. c, Hablutzel, J Helvet. Phys. Acta, vol. 12, p. 489, 



1939. d, Jarre, H., The Brush Development Co. Report to U.S. Signal Corps on synthetic water- 



soluble piezoelectric crystals, April 1, 1948. e, Jarfe, H., personal communication. f, Laboratory 



for Insulation Research, Massachusetts Inst. Techn. Tables of Dielectric Materials III, 1948; and per- 

 sonal communication. g, Landolt Bornstein Tables, 5th ed. h, Mason, W. P., Piezoelectric crystals 

 and their application to ultrasonics, Van Nostrand Co., New York, 1950. i, Merz, W. J., Phys. Rev., 

 vol. 75, p. 687, 1949. j, Mueller, H., Phys. Rev., vol. 47, p. 175, 1935; vol. 58, p. 565, 1940. k, 

 Naval Research Laboratory, Crystal Section. 1, Spitzer, F., Dissertation, GSttmgen, 1938. m, 

 Standards on piezoelectric crystals, Proc. Inst. Radio Eng., vol. 37, p. 1378, 1949. n, International 

 Critical Tables, vol. 6. o, Bever and Sproul, Phys. Rev., vol. 53, p. 801, 1951. 



Fig. 16. — Dielectric constant K a of Rochelle salt. Curve A : free condition (audio 

 frequency); curve B: clamped condition (radio frequency). 



SMITHSONIAN PHYSICAL TABLES 



