Document 8V6na9djYzqv5EjoDg4vzO6Jd

O MO ETHYL CORPOR ON RESEARCH LABORATOR 1600 WEST EIGHT MIEE ROAD FERNDAUE 20 DETROIT, MICHIGAN J- February 1, 1951 Dr. Robert A. Kehoe University of Cincinnati ollege of Medicine den Avenue incinnati 19, Ohio Dear Dr. Kehoe: Inclosed herewith please find a letter from our Dr. Lamb in response to yours of January 18. Sincerely yours. Harold Soroos, Manager Chemical Research Operations HS: gm cc : Mr. C. M. Garabrill Dr. F. Vf. Lamb K E 0020922 ETHYL CORPORATION RESEARCH LABORATORIES 1600 WEST EIGHT MILE ROAD FERNDALE 20 DETROIT, MICHIGAN >: i'V (c January 30, 1951 Dr. E. A. Kehoe University of Cincinnati College of Medicine Eden Avenue Cincinnati 19, Ohio Dear Dr. Kehoe: In connection with preparing standards for our X-ray diffraction ex amination of engine deposits we have made a study of the decomposition products of Pb02, PbCOg and PbO^pbCOg-HpO. It has been found that Pb20g and Pb^Og are both produced as decomposition products of PbQg, the sequence of decomposition products with increasing temperature being, Pb^Og, Pb20g, PbgOij., PbO (red tetra gonal), and PbO (yellow orthorhombic). In the case of PbC03 the sequence on heating in open atmosphere is; PbOPbCOg, 2PbO-PbCOg, Pb20g, PbgOij, PbO (red tetragonal) and PbO (yellow orthorhombic). The first decomposition product of Pb0`2PbC03"H20 is Pb02PbC0g, which is then followed by the same sequence of products as obtained from the decomposition of PbCOg. We are enclosing a sample of Pb20g prepared by heating Pb02 at 380C. for 72 hours in an open atmosphere. This material is identified by our analytical number M-20930 and was found by chemical analysis to have 89.61$ Pb compared with a theoretical value of 89.62. We are also enclosing a sample of Pb^Og prepared by heating Pb02 at 328C. for 72 hours in an open atmosphere. This material identified as M-20835 analyzed 88.92$ Pb compared with a theoretical value of 89.00. The X-ray diffraction patterns of these two compounds indicate them to be isomorphous compounds, how ever, there is no evidence of solid solution at intermediate compositions. At intermediate compositions the patterns (l/k rpm patterns obtained on the new Norelco Spectrometer) show simply mixtures of the two components. It is assumed that the reported pattern for Pb20g to which you refer in your letter of January 18, is that in ASTM Index Card II-II67 taken from the work of A. Baroni, Gazz. chim. ital. 68, 391 (1938). The d values for our preparation of Pb20g are similar to his. In your review of the literature you have no doubt found considerable conflicting data on these two compounds. We have been particularly interested In the work reported by Clark in J.A.C.S. 59, 2305 (1937) in which ''Pb20g" is prepared by a pressure bomb technique from NaQH, Pb02 and H2O. A crystal structure analysis of this material was reported by S. T. Gross in J.A.C.S. 63, 1168 (19kl) In which he found it to be monoclinic and to belong to space group C2il or Cg with a = 7.03, b = 5.62, c = 3.93 A. and /<& = 82. Later, A. BystrBm repeated the preparation and reported a similar crystal structure analysis in Arkiv Kemi, Mineral Gaol. 18a , Wo. 23, p. 1 (I9H). We have been able to prepare a small amount of the same material but not in KF 0020923 N 24418.01 2 sufficiently pure state to permit a chemical analysis which would he satis factory for either confirming or refuting the PhgOo composition. The X-ray diffraction data for our material checked well with the d values calculated from a reciprocal lattice treatment of the above structure data, indicating that we were able to prepare the same product. The X-ray diffraction pattern, however, is entirely different from that obtained on the Pb203 prepared by decomposition of PbOg. We hope to be able to prepare Clark's "PbgO^" in sufficient quantity for a satisfactory chemical analysis so as to determine where it fits into the complicated lead oxide picture. Following the above publication on "Pb203*' BystrSm has reported on the Decomposition Products of PbC>2 and the Oxidation Products of PbO in Arkiv Kami, Mineral Geol. 20A, 1 - (1945)> a long and fairly complete abstract of which appears in C. A. 41, 4053g (1947)- In. this article X-ray diffraction data are given for<phPbOx and jd'PbOx in which x is approximately 1.66 and 1.50, respectively, or Pb^Og and Pb2C>3. The data given agree closely with the data we have obtained for these two compounds. BystrSm compares the data on these two compounds with those obtained by other authors, however, he fails to make reference to his former work on '^203" or to that of Clark's. Another re ference which we have found of interest in connection-with these compounds is that of T. Katz on Contribution to the Study of the Lead-Oxygen System which appeared in Anales de Chimie, (12), 5-65 (1950)* We are continuing to do considerable work on these systems and plan to publish the data obtained on them in the near future. It is hoped that our studies may lead to an answer to the questions, when is a coitpound PbgO^ and when is it not and why? In the meantime, we trust that the enclosed preparations will be of assistance to you in answering your present problem. If you have any comments or suggestions on this subject or if we can be of any further assistance to you on this or related problems we should be pleased to hear from you. Sincerely yours. FWL/dr Enclosed: 2 Samples cc: Dr. H. Soroos Mr. C. M. Cambrill Frances W. Lamb K" 0020924 January 18, 1951 Dr. Harold Soroos Ethyl Corporation 1600 Vest Eight Mile Road Ferndale 20, Detroit, Michigan Dear Doctor Soroos: We have been trying to obtain a small amount of reasonably pure lead sesquioxide (Pb20s) for X-ray difiraction comparison with a material which we suspect is the sesquioxide and which gives a pattern in good agreement with the reported pattern of the sesquioxide. So far we have been unsuccessful and it cccur-red to us that you might have some of this compound or know where we might obtain it. If you could give us some help on this, it would be greatly appreciated. Cordially yours. RAK ef Robert A. Kehoe, M. D. KF 0020925 N 24418.02