Understanding of chemical properties of monovalent transition metal cations in aqueous solutions was obtained by a study of kinetics of reduction of different inorganic substrates by zinc, cadmium, and nickel

Meyerstein, D.

Mulac, W. A.

English

NASA Technical Reports Server

June 1969	 Brief 69-10170 
AEC-NASA TECH BRIEF 
AEC-NASA Tech Briefs describe innovations resulting from the research and development program 
of the U.S. AEC or from AEC-NASA interagency efforts. They are issued to encourage commercial 
application. Tech Briefs are published by NASA and may be purchased, at 15 cents each, from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Reduction by Monovalent Zinc, Cadmium, and Nickel Cations 
This information should prove interesting to chem-
ists and personnel engaged in water pollution research. 
The aim of the present study was to obtain a better 
understanding of the chemical properties of the mono-
valent transition metal cations in aqueous solutions by 
a systematic study of the kinetics of reduction of dif-
ferent inorganic substrates by Zn+ , Cd + and Ni 
The specific rates of reaction of Zn, Cdând Ni 
with 02, N 2 0, H 2 02 , NO,NO 3 , Br0 3
 -, 10 3 -, Cu2, 
and H30+ have been studied and determined , It was 
found that the order of reactivity is Zn > Cd >_ Nit, 
which can be correlated with the electronic structure 
of the monovalent cations. 
All solutions were prepared from triply-distilled 
water and A. R. reagents without further treatment. 
Solutions of 2 x 10-3 M
 of MSO 4 (M = Zn 2 , Cd2or 
Ni 2 ) and I x 10-3 M methanol were used in all experi-
ments. 
Pulse radiolytic experiments were conducted on a 
0.4 sec., 25 MeV electron pulse from a linear accel-
erator yielding a dose of 0.8-6 x 10 19 eV.lH per 
pulse. The OH radicals formed by the pulse reacted 
with methanol, whereas the hydrated electrons reacted 
with M 2+ to give M + . The decay of M + was followed 
spectrophotometrically at 3130 A using a multiple-
reflection cell with a 4 cm long optical cell giving a 
16 cm totallight path. 
All traces were analyzed for first and second order 
decay, and pseudo first order rates were calculated 
when a good first order decay plot was obtained for 
at least three half-lives. 
The measured rates of reaction of Zn+ indicate that 
it is a powerful reducing agent. The Zn+ reactions 
studied fall into the following groups: those which are
nearly diffusion-controlled; those too slow to be meas-
ured with the experimental technique; and N 2 0 (and 
possibly Cu+2) which falls somewhere between the 
extremes. 
The reaction rates of Cd+ are slower, but similar to, 
the corresponding reaction rates of Zn+. Significant 
differences occur only with nitrate and bromate ions. 
The reactions of Ni+ are much slower than the 
others. Only the reaction rate of Ni± with 02 ap-
proaches the diffusion-controlled limit, while most of 
the Ni+ reactions were too slow to be measured. 
Since the absorption bands of Zn+, Cd+and Ni+ are 
similar and have been attributed to charge transfer 
to solvent transitions, one might believe they would 
also react similarly in reductions involving a charge 
transfer mechanism. It is found, however, that there 
is a definite order of reactivity: Zn> Cd>Ni. This 
does not automatically infer the same order for the 
redox potentials of the corresponding M7Mcouples. 
The order of reactivity can be explained by assuming 
that in Zn, the additional electron is located in an S 
orbital where it would be relatively exposed, resulting 
in the fact that Zn is a strong reductant. Also in Cdt, 
the added electron is assumed to be in an S orbital, 
but has a lower reactivity. In Ni+, the added electron 
may enter the 3d shell, an inner orbital. Thus it is 
reasonable that Ni+is less reactive than Zn+ and Cd+. 
Notes: 
Further information is available by D. Meyerstein 
and W. A. Mulac in "Reductions by Monovalent 
Zinc, Cadmium and Nickel Cations," Jour. of Phys. 
Chem., 72, 784 (1968).
(continued overleal) 
This document was prepared under the sponsorship of the Atomic	 liability resulting from the use of the information contained in this 
Energy Commission and/or the National Aeronautics and Space document, or warrants that the use of any information, apparatus, 
Administration. Neither the United States Government nor any per- 	 method, or process disclosed in this document may not infringe pri-
son acting on behalf of the United States Government assumes any vately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19690000170 2020-03-16T17:39:10+00:00Z
2. Inquiries concerning this information may be 
directed to: 
Office of Industrial Cooperation 
Argonne National Laboratory 
9700 South Cass Avenue 
Argonne, Illinois 60439 
Reference: B69-10170 
Source: D. Meyerstein and W. A. Mulac
Chemistry Division

Argonne National Laboratory
(A RG- 10328)
Patent status: 
Inquiries concerning rights for commercial use of 
this innovation may be made to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U. S. Atomic Energy Commission 
Chicago Operations Office 
9800 South Cass Avenue 
Argonne, Illinois 60439
is 
. 
. 
Brief 69-10170	 Category: 03


Reduction by monovalent zinc, cadmium, and nickel cations

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server