Need a really accurate model?
New Cenco-Petersen MOLECULAR MODELS can be quickly hand assembled without special tools for three-dimensional study of stereochemical and conformational factors and reaction mechanisms. Designed to overcome many shortcomings of earlier model systems, they • are made up o f accurate bond lengths ( 1 A = 5 cm). • present precise angles of distortion (to 30°). • can be locked or left free to rotate under stress. • return perfectly to a preset angle. The stereochemist can now directly predict interatomic distances and bond angle distortion using these true-to-scale models. Polyvalent atoms are colored neoprene balls with threaded aluminum inserts placed at the theoretical bond angles. Monovalent atoms are polystyrene with the appropriate bond permanently attached. The bonds themselves may be disassembled and rebuilt with other lengths to provide different scale factors.
cenco ·
ANALYTICAL CHEMISTRY
Facts that speak for
themselves
Resolution with grating-prism combination 0.3 c m - 1 at 900 c m i and 1.5 cm _ i at 3,000 c m - 1 . With NaCl prism 1 cm~i at 900 c m - 1 . Accuracy: routine quantitative intensity measurement at high resolution at 0 . 1 % accuracy down to at least 2 % transmission level. Stray Light: better than 0 . 1 % at 650 c:n-l (grating-prism combination). Reproducibility: transmission—better than ± 0 . 2 % . WaveHumber—better than 0.5 c m ' 1 at 1000 c m - 1 . Vacuum conditions: vacuum conditions for the optical train eliminate unwanted absorptions. Versatility: wide range of operating variables allows ideal conditions to be selected for every analytical problem. T h e rotating prism and grating turntables provide for automatic interchange of the optical system.
For further information and for details of your local distributor, please write to:
UNICAM CO.
/ Subsidiary of Cenco Instruments Corporation 1708 — Irving Park R o a d · Chicago 1 3 , Illinois Mountainside, N. J. Montreal Santa Clara Somerville, Mass. Toronto Los Angeles Birmingham, Ala. Ottawa Vancouver Houston Cenco S.A., Breda, The Netherlands Tulsa Circle No. 44 on Readers' Service Card
82 A
. . . is the judgment of spectroscopists who know the Unicam SP. ioo evacuable Infrared Spectrophotometer. Only the SP. ioo gives peak performance continuously throughout the changing demands of an intensive work schedule. Whatever the requirements — initial resolution at top speeds, single beam working, automatic speed scanning, prism and grating interchange — the SP. ioo achieves them all, easily and precisely at the touch of a button. T h e power to give—and to continue giving top quality performance is the reward of correct design and the best of precision engineering. Check the specification below and then write to us for details of your local distributor. The SP. ioo will be demonstrated during the Eastern Analytical Symposium in New York (2nd—4th November) by the J. C. O'Connell Co., at the Hotel New Yorker, East 34th St., New York.
Reliability: correct design, high quality of construction, plug-in electronic chassis, built-in safety devices and monitoring system prevent accidental damage and ensure long-term reliability.
The complete N o . 71306 Cenco-Petersen Set contains 55 monovalent a t o m s , 59 p o l y v a l e n t atoms, 70 bonds and fittings plus extra parts, all in a partitioned metal case. Send for Booklet 315 for detailed information. $295.00
CENTRAL SCIENTIFIC
EXCEPTIONAL INFRARED PERFORMANCE
SP. 100 Infrared Spectrophotometer UNICAM INSTRUMENTS LTD ·
ARBURY WORKS
Circle No. 157 on Readers' Service Card
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CAMBRIDGE
