AFOSR Scientific Report AFOSR 68-1625 NATIONAL BUREAU OF STANDARDS REPORT 9803 PRELIMINARY REPORT ON THE THERMODYNAMIC PROPERTIES OF SELECTED LIGHT-ELEMENT AND SOME RELATED COMPOUNDS (The previous semiannual reports in this series have the NBS Report Nos. 6297, 6484, 6645, 6928, 7093, 7192, 7437, 7587, 7796, 8033, 8186, 8504, 8628, 8919, 9028, 9389, 9500, and 9601.) <NB^> U.S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS This document is subject to special export controls and each transmittal to foreign governments or to foreign nationals may be made only with prior approval of the AFOSR (SRGL). : Qualified requestors may obtain additional copies from the Defense Documentation Center. NATIONAL BUREAU OF STANDARDS The National Bureau of Standards 1 was established by an act of Congress March 3, 1901. Today, in addition to serving as the Nation’s central measurement laboratory, the Bureau is a principal focal point in the Federal Government for assuring maxi- mum application of the physical and engineering sciences to the advancement of tech- nology in industry and commerce. To this end the Bureau conducts research and provides central national services in three broad program areas and provides cen- tral national services in a fourth. These are: (1) basic measurements and standards, (2) materials measurements and standards, (3) technological measurements and standards, and (4) transfer of technology. The Bureau comprises the Institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology, and the Center for Radiation Research. THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United States of a complete and consistent system of physical measurement, coor- dinates that system with the measurement systems of other nations, and furnishes essential services leading to accurate and uniform physical measurements throughout the Nation’s scientific community, industry, and commerce. The Institute consists of an Office of Standard Reference Data and a group of divisions organized by the following areas of science and engineering Applied Mathematics—Electricity—Metrology—Mechanics—Heat—Atomic Phys- 2 2 ics—Cryogenics 2—Radio Physics 2—Radio Engineering —Astrophysics —Time and Frequency. 2 THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research lead- ing to methods, standards of measurement, and data needed by industry, commerce, educational institutions, and government. The Institute also provides advisory and research services to other government agencies. The Institute consists of an Office of Standard Reference Materials and a group of divisions organized by the following areas of materials research: Analytical Chemistry—Polymers—Metallurgy — Inorganic Materials — Physical Chemistry. THE INSTITUTE FOR APPLIED TECHNOLOGY provides for the creation of appro- priate opportunities for the use and application of technology within the Federal Gov- ernment and within the civilian sector of American industry. The primary functions of the Institute may be broadly classified as programs relating to technological meas- urements and standards and techniques for the transfer of technology. The Institute consists of a Clearinghouse for Scientific and Technical Information,3 a Center for Computer Sciences and Technology, and a group of technical divisions and offices organized by the following fields of technology: Building Research—Electronic Instrumentation — Technical Analysis — Product Evaluation—Invention and Innovation— Weights and Measures — Engineering Standards—Vehicle Systems Research. THE CENTER FOR RADIATION RESEARCH engages in research, measurement, and application of radiation to the solution of Bureau mission problems and the problems of other agencies and institutions. The Center for Radiation Research con- sists of the following divisions: Reactor Radiation—Linac Radiation—Applied Radiation—Nuclear Radiation. 1 Headquarters and Laboratories at Gaithersburg, Maryland, unless otherwise noted ; mailing address Washington, D. C. 20234. 2 Located at Boulder, Colorado 80302. 3 Located at 5285 Port Royal Road, Springfield, Virginia 22151. NATIONAL BUREAU OF STANDARDS REPORT NBS PROJECT NBS REPORT 221- 221-0404 1 January 1968 9803 222- 221-0405 223- 0426 0423 0426 223-0513 313-0430 PRELIMINARY REPORT ON THE THERMODYNAMIC PROPERTIES OF SELECTED LIGHT-ELEMENT AND SOME RELATED COMPOUNDS (The previous semiannual reports in this series have the NBS Report Nos. 6297, 6484, 6645, 6928, 7093, 7 192, 7437, 7587, 7796, 8033, 8186, 8504, 8628, 8919, 9028, 9389, 9500, and 9601.) T echnical Summary Report on the Thermodynamic Properties of Light-Element Compounds Reference: U. S. Air Force, Office of Scientific Research, Order No. ISSA 67-6 IMPORTANT NOTICE documents intended NATIONAL BUREAU OF S ess accounting release by the s subjected to additional evaluation for use within the Government Approved for public e listing of this Report, either in and review. For this reason, t Director of the National Institute of he Office of the Director, Nationa! whole or in part, is not auth> Technology (NIST) Standards and by the Government agency for which Bureau of Standards, Washing for its own use. the Report has been speciticall on October 9, 2015 copies <NB£p> U.S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS ABSTRACT Thermodynamic and related properties of substances important in current high-temperature research and development activities are being investigated under contract with the U. S. Air Force Office of Scientific Research (USAF Order No. ISSA 67-6) and the Advanced Research Projects Agency (ARPA Order No. 20). This research program is a direct contribution to the Interagency Chemical Rocket Propulsion Group (Working Group on Thermochemistry) and, simultaneously, to other organizations oriented toward acquiring the basic information needed to solve not only the technical problems in propulsion but also those associated with ballistics, reentry, and high-strength high-temperature materials. For given substances this needed basic information comprises an ensemble of closely related properties being determined by an extensive array of techniques. Some of these techniques, by relating thermodynamic properties to molecular or crystal structure, make it possible to tabulate these properties over far wider ranges of temperature and pressure than those actually employed in the basic investigations. This report presents the results and interpretation of five recent NBS experimental studies of thermodynamic properties, two reviews which refine data treatment and evaluation, and one new critical assessment of published heats of formation. The heat capacity of beryllium nitride, Be3N2, was precisely measured from 0 to 315 K; after judicious correction for the irreducible impurities, the data led to the common thermodynamic properties from 0 to 315 K, complementing earlier NBS measurements from 273 to 1173 K. Precise high-temperature calorimetry gave the heat capacity of tungsten from 1100 to 2600 K (showing no detectable difference between two samples, one triple -zone -refined and 99 * 999% pure); finally corrected results are given also for solid and liquid beryllium aluminate, BeA^O^, from 1200 to 2 J4.OO K. A mass- spec trome trie investigation of A^2^3 containing 5 * 8% BeO identified the high-temperature gas species and gave values for their standard i . heats of formation. As part of the current NBS microwave and infrared investigation of the alkali -hydroxide molecules, the high-temperature microwave spectra of four isotopic varieties of RbOH were observed and analyzed to give their molecular constants; like CsOH (studied earlier ), RbOH is linear, with a low-frequency bending vibration of large amplitude. Two reviews deal with reaction calorimetry involving fluorine compounds: One documents the inadequacy of estimation rules for unmeasured inorganic fluorides, and recommends a systematic cataloging of results to achieve better consistency; while the other de- scribes a new computer subroutine for the automatic reduction of bomb -calorimetry data on organic fluorine compounds. As the result of an up-to-date critical evaluation of the published data giving AHf^g, AGf^g? an(* ^298 mgnes ium compounds, values are documented and tabulated for 60 species of interest in "light-element” applications Thomas B. Doug/Las Project Leader iy_ Charles W. Beckett Assistant Division Chief for Thermodynamics Heat Division, Institute for Basic Standards ii TABLE OF CONTENTS Page Abstract i Chap. 1. THE THERMOCHEMISTRY OF INORGANIC FLUORINE COMPOUNDS. THE NEED FOR A CATALOG OF THERMOCHEMICAL PROCESSES (by George T. Armstrong) ! ! . 1 1. Estimates of Heats of Formation . 1 Table 1. Accuracy of Estimates of Heats of Formation of Some Fluorine Compounds 2 2. Some Sources of Experimental Difficulty in Measurements ... 3 Table 2. Successive Determinations, A H 0 0 . f [^203 ( , )] 3 3. Cataloging the Calorimetric Processes 6 References to the General Text . 9 Table 3« Thermochemical Studies Involving Tetrafluorome thane 11 Notes to Table 3 . 12 References to Table 3 • 15 Table b» Process for AHf[CHj,(g)] from Reactions of Table 3 • 16 Fig. 1. Recent information on the heat of formation of aqueous hydrofluoric acid • 17 Chap . 2 . HEAT CAPACITY AND THERMODYNAMIC PROPERTIES OF NITRIDE, Be FROM 20 TO 315K BERYLLIUM 3N2 , (by George T. Furukawa and Fkrtin L. Reilly). 19 Abstract 19 I. Introduction 19 II. Apparatus and Method 19 Ill . Sample 20 IV. Results 23 V. References . 25 Table 1. Summary