Direct methods in crystallography (Woolfson, M. M.)

Thew t~chniqurs ar? usnally formu- lnted in trmm of n ... tage is that t,hey are almost completely objcetivr, and their ... somewhat more than casual...
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gI:~sscs, and other sperial solid-state systems as samples; gxscs and gas-disp m o i d s a s samples; poI~rizat,ionand spertrol~oli~riaation techniques; r and m v i h e s ; quenching; comparative spcrtromptry: sorptives and molecular films; and, advanced instruments like the highly prol,able forthcoming interference spertrofloorometcr. JACK DE MENT

De Ment Lahoralories Portland, Oregon Direct Melhodr in Crystallography

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Ilrooljson. Oxford, At the Clarendon Press, I9G1. viii 14-1 pp. Figs. and tnbles. 14.5 X 22 em. $4.80.

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T h r term "direct methods" means, in t h e dmvt. eontcxt, met,hods for deriving t h e p h i ~ + eof~ ohserved stmctorr nmplitudcs by purrlg !mathemstid means nnd thus going " d i r ~ c t l j " from the ohs~rvecl ditlrnrtion data from a crystal t o thp calculation of t h r electron density in t h r unit. e d . Thew t ~ c h n i q u r sar? usnally formulnted in trmm of n set of mat.hematicnl steps which HPP t o hc carri~dout in a rout,irw ~ s yand , w r y often ~ w p i r ethe use of an elcrtlxmic computer. Their advantage is t h a t t,hey are almost completely objcetivr, and their grcxtrst disadvantage is t,hat they are almost e o m p l ~ t r l y01,jrctive. This monograph recounts the history of direct methods beginning v i t h thrir inception in 1!l48, and following t,llrongh t h e many suhsrquent suggcstions down t o t h e pres~nt,.A very uscful fenture is the illus tration of some of tho "&hods hy t h e prcsentat,ion of simple examples whirh t h e reader may t r y for himself (the solutions are e v ~ n at t h e end of the lrook). The style of t,hr author is admirahlv clcar, and he has tnkcn t h ? trouble t o rework maqv of thc soggrstrcl nlethods in order that thepresentation may Re as lucid as possible. Thp author points out t h a t the record of the st,ruetures which have thus far been solved by direct mcthads is, st the prcsrnt timnc, rstrnsivr hut not impressivr. I n other words, t h e standard mcthods for stn~et,urpdetermination arc hy no means ahsol&. On t h e other hand, he feels t h a t in mother decade direct methorls will be of major importance. This means t h a t the determination of structures will be relegated t o technicians. The r e v i ~ m awaits r this prcsurnetl drvelopment n-ith great interest. Finally, the author of this charmingly writtm littlr hook warns the prospect.ive rexdrr in the preface with t h e follorl-ing statement: "For the stranger or t h e compnrativr newcnmcr t o t h e field of crystallography this monograph is not recommmdcd; indeed a more unsuitable avenue of approach could hardly he imagined." This r r v i ~ w wis in complete agreement with t h e above statement. This monograph can he recommended, howcver, t o experts in t,he field, and t o those whose knowledge of structure determinations is somewhat more t h a n casual. It should he required rending in any graduate course in X-ray erystnllography. JERRY DONOHUE Universilz, of Southern Cal