MODES OF MOTION IN QUARTZ CRYSTALS 95 



C23 = cisic* + s*) 4- (di + C33 — 4^44)^^ — 2cu{c^ — s )sc 



C2i = Cu{As'^ — \)C^ + [CnC^ — C335^ — (2C44 + C13)(C — s )]sc 



Czi = —cui'ic^ — 1)^" + [cns' — C33C' -\- i2c44 + Cn)(c — s )]sc 



C&6 = Cu{c — 5 ) + (f66 — Cii)sC 



<^16 — ^16 — ^26 — ^26 — ^35 — f36 — ^45 — C46 — U 



S\\ = Su 



522 = SnC + 5335 + (544 + 2513)5 C + 25145C 



533 = ^11-^^ + -^33^ + (-^44 + 2513)5 C — ISuS^C 



544 = -^44 + 4(5ii + -^33 — -5^44 " 25i3)5V — 45u(c — ^ )SC 



S%h = -^44^ "f" -^ee^ + 45i45f 



■^66 = ■^44-^ "f" Sn^C — 45i45C 



' 2,2 



5i2 — ^^12^ I S\Z^ — 5l45C 



' 2 I 2 I 



5i3 = 5i25 4- 5i3C + 5i45C 



5(4 ^ Su{c — 5^) + 2(512 — S]s)SC 



Si3 = Snic + 5^) + (511 4- ^33 — .^44) A^ — 5i4(c — 5 )sC 



524 = ."^14(45^ — 1)C^ + [2(5iiC^ — 5335^) — (^44 + 25i3)(c^ — S'y\SC 



^34 = — 5i4(4c^ — 1)5^ + [2(5u5^ — 533C^) + (^44 + ISy^if — 5^)]5C 



^56 = 25i4(<:^ — 5^) + (566 — ^44)^^ 



•^16 = -^16 = -^25 — -^26 — -^36 — -^36 — -^45 — 546 — U 



d\\ = Jii 



d\i = — {dxi^s + d\\c)c 



dvi — (diiC — dus)s 



du = d\i{c — 5 ) — 2di\sc 



dih — — (duC + 2dns)c 



dit = {d\\S — 2d\\c)c 



d'zi = — {duc + 2^115)5 



dz^ — {dus — 2di\c)s 



d\b = d\z = C?21 = d22 = <^23 = <^24 = <^31 = <^32 = <^33 = ^^34 = 



