and Joe Vikin' N e w York City Community College City University of N e w York Brooklyn
I
Fusion Reactions Under the Microscope
The traditional way of conducting fusion reactions is by the use of a platinum wire mounted on a glass rod, and a Bunsen burner. I n this manner, with the use of fluxes, colors are obtained which are characteristic of the ion present (1). I n this work we used an electrically heated wire, a technique originally snggested by Emich and subsequently used in metallurgical research (2). When the flux was found to react with Pt, a Ni wire was used. This technique is advantageous in that the yellow coloration produced in the flame by certain ions does not mask the color of the bead, since in some cases the observation must be made while the bead is still hot. Also, there is no overlapping of the oxidizing and reducing zones, as happens in the flame. An ordinary rheostat is used to control the amount of current flow, and a variable resistance is used to control the temperature of the wires. For work below 10O0C,a 36-gauge platinum wire was used; for higher temperatures, 26-gauge wire. A low magnification microscope is sufficient for this purpose. A small portion of the flux was melted on the wire; the melt was allowed to cool and an aliquot of the solution under study was placed on the melt by means of a l-pl pipet. The temperature was raised slowly to evaporate the water, then raised higher until the color developed.
Table 1 . Limit Cation (UE)
Flux
Co(I1) Mn(I1) Cr(II1) Tr(VII ~,
0.4 0.8 0.9 1.7
Borax Borax Borax Borax
Fe(II1) Ni(I1)
0.9 0.7 4.0 0.7
Borax Borax Borax Borax
U(VI)
Cu(I1I . .
Detection of Cations Color
W(V1)
3 0 . 0 Microcosmic salt
Mo(V1)
5 . 0 Microwsmic salt
Fe(II1)
0 . 3 Microcosmic salt
Blue Violet Green Yellow when hot. colorless when col Yellow Reddish brown Pale yellow Yellowish when hot, blue when cold Yellow when hot, colorless when cold Greenish yellow when hot, brownish orenae - when
wid,
Greemsh yellow when hot, dark green on continued heating, colorless when
UxZ "."W
KOH XNOs &hydroxyquinaline &hydroxyquinoline 8-hydraxyquinoline R-hydroxyquinoline &hvdroxvouinoline
reen, darkens on standing Green Yellow Bright red Blue-black Blue-black Reddish brown Green
Cations
Table 1 gives a summary of the results obtained in the detection of cations, along with the limit of identification and the experimental conditions. Borax was the easiest flux to work with because of its low melting point and its ability to react with many ions to give characteristic colorations. Sodium hydrogen ammonium phosphate, or microcosmic salt, was tried with several cations which gave colorless beads with borax, and positive results were obtained with W, Mo, and Fe. I n an attempt to find a suitable reducing medium, sodium hypophosphite was used (5-5). This salt was tried with lVIo and W, which gave negative results with the first two reagents. I n order to avoid the use of platinum, which is strongly attacked by the hydroxides and nitrates of the alkali metals, a 24-gauge nickel wire was used; with the Ni wire it was possible to detect Mn and Cr, with NaOH, KOH, and KN03as fluxes. West and Grauatelli (6) used 8-hydroxyquinoline as a flux to identify several inorganic ions. With the present technique, it was possible to dctect the presence of Cr, V, Fe, U, and Ni. This paper is taken in part fmm the M.A. thesis of J. Vikin, Brooklyn College, 1964. The junior author is greatly indebted to the h t e Professor Anton A. Benedetti-Pichler, who suggested this topic, for his invaluable advice, criticism, and guidenee.
Anions
An effort was made to detect anions by means of this technique. Positive results were obtained with the chloride, sulfate, and carbonate ions. The results are summarized in Table 2. I n all cases boric acid was used as the flux. Table 2.
Detection of Anions
Anion
Limit Gg.)
Flux
Chloride Sulfate Carbonate
1.3 1.3 2.0
HsBOs HaBOa H.BO.
Wire
Detecting Agent
P t 0.1M solution of AgNOs P t 1M solution of BaCL P t Phenolrrhthelein-NB~COS
For the detection of the chloride ion, a drop of AgNOz is placed on a slide, which then is placed above the loop of the platinum wire. The liberated HCI reacts with the AgN03 solution, causing the formation of AgCI, whose presence was confirmed by the method of Feigl (7). The sulfate ion was collected in a drop of 1 M solution of BaCl*. The presence of the white curdy precipitate of BaSo4revealed the presence of this anion. To detect the carbonate ion, the liberated COz is detected by means of the phenolphthalein-Na2C03 Volume 43, Number 8, August 1966
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reagent (8). A drop of this reagent retains its color for a t least 10 minutes, but care must be taken that the reagent does not evaporate, since this causes loss of color and it may be mistaken for a, positive result. No discoloration of the reagent results when a drop of the reagent is held over fused boric acid. Literature Cited ( 1 ) TREADWELL, E. P., AND HALL,W. T., "Analytical Chemistry. I. Qualitative Analysis," 9 t h English ed., John Wiley & Sons, Inc., New York, 1959, p. 7 4 .
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(2) KOCH,W., MALISSA, IT., DITCES,D., Arrh. Eisenhz~ettenu,., 2 8 , 7 8 5 (1957). (3) CRAWFORD, T. C., AND ALLEN,J. E., J. Geol. Education, 8 , 11 (1960). (4) VAN H. B., AND CRAWFORD, T. C., Ind.Eng. Chem. (Anal. ed.) 13, 459 (1941). ( 5 ) RAMMELSBERG, C., J. Chem. Soc., 26, ( I ) , 18 (1873). (6) WEST, P. W., AND GRANATELLI, L., A w l . Chem., 24, 870 (1952). . . (7) FEIGL,F., ('Spot Tests in Inorganic Analysis," 5th English ed., Elsevier Publishing Co., Amsterdam, 1958, p. 32. ( 8 ) FELCL, F., i b i d , p. 337.
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