cilitates the construction of actual three-di- mensional models of complex structures.

Any structure can he converted to a erauhic reoresentation of a suace-filling mobel. ~ 0 t h the atomic radius and the color ~ ~~~ ~~ ~~~~~ ~~ ~ ~

in a hich aMma are plutted on thewreen are determined by the typeot atam indicated hy the label given to that atom a t the time the coordinates are entered.

Up to 20 different data files can be drawn on the screen simultaneously, and the most recently added structure can be manipulated independently of the previous- ly added ones. This permits a "docking" function, where, for example, a substrate can be moved into position a t the active site of an enzyme. While manipulating struc- tures, users can simultaneously monitor the interatomic distances between as many as three pairs of atoms.

The stereochemistry of a molecule on disolav also can he inverted. When com- hinedkith the ability of the program toma- nipulatr two structures indeprndently, it hecmws possiblp t,, draw a molecule next to its mirror image and test for superimposahi- lity and therefore chirality.

Color can he used to denote either depth from the viewer or atom type. Al- though valuable, this feature is fundamen- tallv limited bv the choice of onlv three fore- , ground cdc,rs'in HASICA. C& is put to wry nod use by one ieature u hich pluts m e structure (rotated by 5 degrees about the y- axis) on top of a second. If the first is plotted in red, and the second in green, the use of red-green glasses converts the image into a three-dimensional representation of the molecule. In practice, this feature is disap- pointing with a medium resolution screen. The manual suggests much better images will be obtained with a high resolution (RGB) monitor. Without access to such a monitor, I was unable to verify this state- ment.

Printer listings of coordinates, connec- tivities, and interatomic distances are readi- ly available. A screen dump of the graphics image also can be obtained on a graphics printer, provided the user has the necessary utility software (GRAPHICS.COM in DOS 2.10).

Student Reactlon This program was used as an option for

several first-year general chemistry stu- dents and for aspecific assignment withsec- ond-year organic chemistry students. It was used both on IBM PC and PCjr microcom- puters. I found it necessary to prepare a supplemental sheet giving several examples to help the organic students perform super- impasability studies on simple chiral mole- cules. Students generally did not feel a pra- gram such as this could replace molecular models, but they thought i t would augment their use, and might actually assist them in makine models of comolex structures from X-my crystal darn R'ithuut rxception, btu- r l ~ n t s ~njm.rd the pnl,gram, and were rea- sonshly n ~ n v m a n t w t h the main menu op- tions in one to twa hours. They particularly appreciated the dynamic motion and space- filling model features of the program. Sever-

al students criticized the organization of material in the manual that accompanies the program. Students also suggested add- ing several examples of the manipulation of molecules, particularly relating to the inver- sion, orientation, and superimposability features of the program to help them be- come familiar with the available options.

Overall Assessment

Molecular Grauhics is one of the first ver- satile entries into the aoolicetion of micro- ~~~~~ ~~~~~ . . ~~ ~~ ~~ ~

computer graphics ior purpose, of risualiz. ing three-dimensional structure. The pn,- gram is innovative and offers a considerable range of options once the Cartesian coordi- nates have been generated for a structure. I believe that the program may even have ap- plications to nonchemical systems, allowing data which can he entered in the form of Cartesian coordinates to be readily visual- ized and manipulated in space. The limita- tion of three foreground colors will be re- strictive for many applications. Further- more, unless a user has access to a color graphin printer, most vivid three-dimen- sional images will he left in the mind of the viewer.

Molecular Graphics will probably prove most useful to students in organic and bio- chemistry courses. Some obvious education- al applications are for the visualization of crystal structure data for large molecules, where building a molecular model would be tedious, examination of structnre-reactivity relationshins in biaoreanic chemistrv. and . . carrying o;t superimp&ahility studies.

Given the great deal of attention paid to the development and refinement of the pm- gram, i t is disappointing that a similar effort was not paid to the accompanying manual. I t was originally well conceived, but when the program was revised and enhanced, the changes in documentation simply were add- ed to the end of the manual that had already been published. This leads to considerable confusion for first time users who must of- ten go to a t least two places to find informa- tion on a single feature. For a t least one feature (three-dimensional representation using redlgreen structures), important in- formation is contained in the original refer- ence and then not repeated in the new sec- tion that describes that option. Clarity in documentation is particularly important if the program is to be used successfully in introductory and lower level courses.

Peter G. Mahaffy The King's College

10766-97th Street Edmonton. Alberta, Canada TSH ZM1

Molecular Animator, IBM PC Verslon J. Jeffrey Howbert, COMPress, A Division of Wadsworth. Inc. P.O. Box 102, Went- worth, NH 03282

Hardware: IBM PC Components: 1 disk with backup, User's

Manual Level and Sublect: Any chemistry course in

which molecular structure is discussed. cost: $95.00

Review I The Molecular Animator is s modeline

prugram that alloxs thr user to display and umitrurt ball-and-stir< mudels uf organlc and inorganic molecules. Thi, sotruarc package provides a unique opportunity for teacher and student alike to explore graphi- cally a variety of geometric forms associated with molecular structure. Primarily intend- ed for students with some exposure in the fundamentals of chemical hondine. this mo- . gram raanexcelltnt vehicle i n \\ hich to view

the depth in all threp dimensions, ln a con- vmring fashion,oisurh nvtaolrs as thechair and boat conformations of cyclohexane, the planarity of aromatics like hennent. ur the octahedral arrangcrnrnr of driulfurdcca- fluoride. 1 found m e o i its attributrs to he the mare than 20 typical molecular struc- tures. includine those listed above. that can ~ ~. be displayd in front of n large lrrture rev- tion on aaorren thruughaprqection dpwrc. This latter vharacrerisr~c ha\ many advan- tages over the omnipresent overheadprojec- tor with two-dimensional transparencies, or attempts, futile as they are, to build a model of a molecule from a kit large enough to be seen well by all in the class, or worse yet, the practice still common with the artists among us to draw structures on the chalk- board, a practice that baffles our colleagues in business and industry. While one mole- cule is displayed on the screen, or monitor, the user can manipulate, by a single stroke of the function keys, the structure to rotate about its center of mass in either direction along an x, y, or z axis, a t slow or fast speeds. It can also be made to stop in any position, he enlarged, or reduced in size, and, as a ball-and-stick model, it can be displayed or rotated as just a stick (wire frame) or as just atoms in the full model.

Students in my second-semester General Chemistry class used the program individ- ually and found it to be far more helpful in understanding the full picture of molecular geometry thanjust relying on textbook illus- trations and one's imagination. Though I did not have such a class a t the time, I be- lieve from past experience that introductory organic chemistry students would benefit greatly not only from the ready display models, hut also from the flexibility to con- struct their own models from the various editors and menus that are accessed easily, and from the ample instructions given in the User's Manual. Their newly constructed models can then be saved and stored on a second formatted disk. Most of my students seemed to feel a t ease with the utilization of the main menu and the displaying of the stored figures from the files, but they were more tentative about the construction of models. They seemed also to marvel a t their ability to manipulate the rotation, size, and direction in which the structure moved by use of the function keys. Yet I also detected that they tended totire after an hour or so of working with the shapes stored on the main disk, which is why, I believe, their overall evaluation tended toward good rather than excellent. But this is not unusual for any chemistry student today considering that most of them are not chemistry majors and view the subject matter with some amount of reproach and scepticism as to its reie- vance for their chosen vocations. Because of its ease of use and pedagogical value, the Molecular animator ranks as a significant

A88 Journal of Chemical Education

user. If i t were written far the structural novice. then there is not enoueh information " in the oroeram tomakeiteasv to usennd the . ~ ~ ~ ~~ ~. ~~ ~~-~ ~~~~~~ ~~~~

process of molecule construction is compli- cated. If it is for the professional chemist, then the program is too limited. The design doesnot seem to satisfy the requirements of either group, and the intellectual rewards of the program are limited in comparison to the effort required for its use. Buildingplas- tic models is easier and as informative. This progrom would hrncfit greatly through rhr enhanced nuw of color, a~cesd , l e ~ ~ P C I I I R I infwnarron, nnd a discussion of inorgnnlr applications in the text as well as more ex- amples of structures in the program. An in- teresting addition would be to include VSEPR theory by having the user input data about atom types, bonding pairs, lone oairs. and have the oroeram draw the mole- . .. h , drfine nand angles. and animate it for the user. There rnhancemtnL~ would pro- virk n more u~eful and complete package.

Richard E. Palmer Department of Genetics University of Wisconsin

Madison. Wi 53706

E~IIOT'S Note: The Apple I1 family version of this SOnWare was reviewed in the November 1987 issue of this Journal.

Titles of Interest -1986-

Metal Complexes in Solution Everen A. Jenne and Enrio Rizzarelli, et al., Editors. Piccin Nuova Libraria, Padova, Italy, 1986. viii + 317 pp. Figs. and tables. 17.2 X 24 cm. 540.00.

Proceedings of the International School in Metal Complexes in Solution held a t Por- tieello, Palermo, Italy, October 3-8,1983.

Applied Geothermics Michael J. Economides and Plene 0. UR gemach, Editors. Wiley: New York. NY, 1987. xiii + 238 pp. Figs. 17 X 25 cm. $69.95.

The aim of the editors of this hook is to provide a state-of-the-art report of current research in geothermal energy.

Aquatic Surface Chemistry: Chemical Processes at the Particle-Water Interface

Werner Stumm. Editor. Wilev: New York. NY. 1987. xix + 520 pp. ~ i & . and tables. 16.8 X 24.3 cm. $69.95.

This monograph brings together new findines and innovative oraoosals in the

ing author presents the general principles behind a specific chemical process, then ex- plores the results and implications of recent &arch. Interactions a& explained from a mechanistic and dynamic point of view rather than a descriptive one.

Binding Constants: The Measurement of Molecular Complex Stability

Kenneth A. Connors. Wiley: New York, NY, 1987. xiv + 411 pp. Figs. and tables. 15.9 X 23.5 cm. $69.95.

This volume describes methods for the measurement of bindine constants for com- " d e x formation in solution-alone with dis- .~~~ ~ ~~

~ ~

cuaiionr of prrtinrnt thermodynnmici. modeling stntirtics, and regression analyiii. I t also covers all of the experimental meth- ods useful far measuring these equilibrium constants.

An attempt is made toward a systematic compilation of information on binding con- stants from the literature of studies as di- verse as acid-base chemistrv. metal ion co- . . ordinoriun compound^, hydrogpn bunding. chnrgr transfer complrxation, nydrophnhw intrmction,and protrm binding. Nen marr- rial introduced here includes more modern approaches to random association (contact complexes), methods of selection of stan- dard sites, and com~arison of results. The treatment of nonlinear least squares regres- sion is more detailed than usual.

Carbohydrates P. M. Collins, Editor. Chapman and Hall: New York. NY. 1987. xi + 720 pp. 21.4 X 28.2 cm. 5175.00.

This latest volume in the series Chapman and Hall Chemistry Soumebooks, the aim of which is to provide carefully tailored in- formation to individual workers in particu- lar arens of rherniirr) and biorhemicrry.

The ~ n f ~ r n a a t i m in rhiq vulumr is parrial- I S ~ C I I V P ~ from the Fitlh Icditiun ofthe TJlr- tionary of Organic Compounds, published in 1982, and its annual supplements. Each individual entry has been reviewed and up- dated and a large number of totally new entries have been added. In addition, many hundreds ofadditionel synonyms and deriv- ative molecular formulas have been added to the existing entries, thus enhancing the utility of the Name and Molecular Formula Indexes.

Catalyst Design: Progress and Perspectives

L. Louis Hegedus, Editor. Wiley: New York. NY. 1987. xi + 288 pp. Figs. and tables. 15.4 X 23.6 cm. $47.50.

Contemporary Themes in Biochemistry. Volume Vi, ICSU Short Reports 0. L. Kon, M. C.-M. Chung, et aL, Editors. Cambridge University: New York, NY. 1987. xxxvii + 715 pp. Figs. and tables. 15.8 X 23.6 cm. $49.50.

Proceedings of the 4th Federation of Asian and Oceanian Biochemists Congress, Novemher 30-December 5,1986.

Diagnostic Enzymology David Hawcroff Arthur M. James. Editor. Wiley: New York, NY, 1987. xxi + 280 pp. Figs. and tables. 15.1 X 22.8 cm. $21.95.

This book, another in the ACOL series, describes the nature of enzymes, the tech- niqars usrd tor measuring en7yme a r t ~ \ i t y and the problems assuriated with obtaining rroroducihle and mranineiul results. The final section discusses the importance of en- zyme assays in the diagnosis of human ill- ness and the monitoring of treatment and recovery to put the methods and interpreta- tion previously described into context. Ref- erences are included so that the basic intro- duction supplied here can he extended by those interested in reading further.

Handbook of Separation Process Technology

Ronald Rousseau, Editor. Wiley: New York. NY. 1987. xiv + 1010 pp. Figs. and tables. 16.6 X 24 cm. $69.95.

High Performance Liquid Chromatography in Enzymatic Analysis

EdwardF. Rossomando. Wiley: New York, NY. 1987. xv + 253 pp. Figs. and tables. 15.7 X 23.5 cm. $39.95.

This small book describes the HPLC method and explains and illustrates its use. Eachchapter deals withadifferent aspect of the method, beginning with an overview and ending with a detailed summary. Through- out, an attempt is made to focus on ques- tions related to the assay of the activity of an enzyme rather than its purification.

A90 Journal of Chemical Education