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Richard A. Robie

Publications and source records attributed to Richard A. Robie.

24 records · Page 2Linked to original sources

X-ray crystallographic data for minerals

X-ray crystallographic data are of particular importance to the mineralogist. Beyond the considerations of structural chemistry they provide. one of the most accurate methods for phase and/or compositional determination and for obtaining _the molar volumes and densities of minerals {Robie and Bethke, 1962).

Trace Elements Investigations

Molar volumes and densities of minerals

These tables present critically chosen "best values" for the density and molar volume of selected mineral compounds. No attempt was made to be all-inclusive; rather we have tried to present data for chemically and physically well-defined phases for which the molar volume and/or density was knovvn to the order of 0. 2 percent.

Trace Elements Investigations

Thermodynamic properties of minerals

In the ten years since the publication of the national Bureau of Standards comprehensive tables of thermochemical properties, by Rossini and other (1952), a very large body of modern calorimetric and equilibrium data has become available. Because of the complex interrelations among many thermochemical data and the necessity for internal consistency among these values, a complete revision of this standard reference is required. This is also true of the summaries of thermochemical data for the sulfides (Richardson and Jeffes 1952) and for the oxides (Coughlin 1954). The following tables present critically selected values for the heat and free energy of formation, the logarithm of the equilibrium constant of formation Log K f , the entropy and the molar volume, at 298.15°K (25.0°C) and one atmosphere for minerals.

Trace Elements Investigations

Physical properties of salt, anhydrite and gypsum : preliminary report

This summary is the result of a search of the available literature. Emphasis is placed on the mechanical and calorimetric properties of salt; the measurements of elastic, thermal, magnetic, and mass properties of salt are merely tabulated. Under hydrostatic pressure < 1,000 kg/cm2 at room temperature, salt deforms plastically to strains > 100 percent at a nearly constant stress difference of about 300 kg/cm2. Similarily, under temperatures > 400?C at one atmosphere, salt deforms plastically to strains > 100 percent under stress differences of about 100 kg/cm2. Entha1pies were calculated for various temperatures to 2,000? C from the low temperature and high temperature heat capacities and the heats of solution of the following minerals: salt (or halite), NaCl; anhydrite, CaS04; quartz, Si02; and calcite, CaC03. Three combinations of these minerals were assumed to represent three possible natural salt beds, and the heats required to raise the temperature of each to 1,500?C and to 2,000?C were calculated. For a half and half mixture of salt and anhydrite, 1,300 cal/gm were required to raise the temperature to 2,000?C. For an evaporite containing 60 percent salt and about equal amounts of anhydrite, calcite, and quartz, 1,100 cal/gm are required to raise the temperature to 2,OOO?C. Most of the measurements of the elastic moduli were made on single crystals of salt, anhydrite, and gypsum. For the most part, the measurements of density, magnetic susceptibility, and other properties were made on natural salt samples.

Trace Elements Memorandum