geologia: Mercury (element)

Evidence: 100 • authority: 72

Mercury is a chemical element; it has symbol Hg (from Latin hydrargyrum) and atomic number 80. It is commonly known as quicksilver. A heavy, silvery d-block element, mercury is the only metallic element that is known to be liquid at standard temperature and pressure. As well as having the lowest freezing point, mercury has the lowest boiling point and subsequently the narrowest liquid state range of any metal at standard conditions. Mercury occurs in deposits throughout the world mostly as cinnabar (mercuric sulfide). The red pigment vermilion is obtained by grinding natural cinnabar or synthetic mercuric sulfide. Exposure to mercury and mercury-containing organic compounds is toxic to the…

Evidence: 73 • authority: 92

A Nonhazardous Alternative to Mercury in Liquid Intrusion Porosimetry: Systematic Study of Intrusion/Extrusion Behavior of a Gallium-Based Liquid Metal (eGaInSn) into Meso- and Macroporous Silica, Alumina, and Carbon Materials.. Mercury porosimetry is considered the standard method for the characterization of macroporous solids. However, health risks and environmental concerns make a replacement for mercury sought-after. Despite many advances in various techniques, so far, no alternative method is available. Here, we introduce a novel method using, instead of mercury, eGaInSn (Galinstan), a nonhazardous, eutectic gallium alloy, liquid at ambient temperatures, which is already widely used as…

Evidence: 73 • authority: 72

A liquid metal is a metal or a metal alloy which is liquid at or near room temperature. The only stable liquid elemental metal at room temperature is mercury (Hg), which is molten above −38.8 °C (234.3 K, −37.9 °F). Three more stable elemental metals melt just above room temperature: caesium (Cs), which has a melting point of 28.5 °C (83.3 °F); gallium (Ga) (30 °C [86 °F]); and rubidium (Rb) (39 °C [102 °F]). The radioactive metal francium (Fr) is probably liquid close to room temperature as well. Calculations predict that the radioactive metals copernicium (Cn) and flerovium (Fl) should also be liquid at room temperature. Alloys can be liquid if they form a eutectic, meaning that the alloy…

Evidence: 63 • authority: 72

Group 12, by modern IUPAC numbering, is a group of chemical elements in the periodic table. It includes zinc (Zn), cadmium (Cd), mercury (Hg), and copernicium (Cn). Formerly this group was named IIB (pronounced as "group two B", as the "II" is a Roman numeral) by CAS and old IUPAC system. The three group 12 elements that occur naturally are zinc, cadmium and mercury. They are all widely used in electric and electronic applications, as well as in various alloys. The first two members of the group share similar properties as they are solid metals under standard conditions. Mercury is the only metal that is known to be a liquid at room temperature – as copernicium's boiling point has not yet b…

Evidence: 54 • authority: 72

Vapor pressure or equilibrium vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a liquid's thermodynamic tendency to evaporate. It relates to the balance of particles escaping from the liquid (or solid) in equilibrium with those in a coexisting vapor phase. A substance with a high vapor pressure at normal temperatures is often referred to as volatile. The pressure exhibited by vapor present above a liquid surface is known as vapor pressure. As the temperature of a liquid increases, the attractive interactions between liquid mo…

Evidence: 48 • authority: 92

Mercury vapor generation using a non-equilibrium cold atmospheric plasma jet for mercury determination equipped with atomic absorption spectrometry.. Cold vapor atomic absorption spectrometry (CV-AAS) is a cost-effective and simple technique for determining mercury (Hg). However, it typically requires milligram amounts of another toxic heavy metal, tin (Sn). We developed a novel Hg determination method that integrates a low-temperature atmospheric-pressure plasma jet for Hg atomization with an atomic absorption spectrometer, and called it plasma-mediated vapor generation AAS (PMVG-AAS). Unlike conventional CV-AAS, this method does not require Sn because plasma-generated reactive species red…

Evidence: 45 • authority: 80

Standard Test Method for Wax Appearance Temperature and Wax Disappearance Temperature of Petroleum Products and Liquid Fuels

Evidence: 45 • authority: 80

THE EFFECTS OF TEMPERATURE AND COMPOSITION ON THE MERCURY VAPOR PRESSURE IN THE URANIUM-MERCURY SYSTEM

Evidence: 45 • authority: 80

MERCURY, LIQUID AND SOLID, UNDER PRESSURE

Evidence: 45 • authority: 92

Realizations of the triple points of carbon dioxide and sulfur hexafluoride-ITS-90 temperature determinations and interpolations.. The triple points of carbon dioxide (TP CO 2 ) and sulfur hexafluoride (TP SF 6 ) have been studied over the last decade as alternative fixed points to the triple point of mercury (TP Hg, 234.3156 K) on the International Temperature Scale of 1990 (ITS-90). NIST has been developing TP CO 2 and TP SF 6 cells to be employed as drop-in replacements for TP Hg cells for calibrations of standard platinum resistance thermometers (SPRTs). This work presents the results of the assessment of new immersion-type CO 2 and SF 6 triple point cells built at NIST and the results…

Evidence: 45 • authority: 72

Pressure measurement is the measurement of an applied force per unit area by a fluid (liquid or gas) on a surface. Pressure is typically expressed in units of pascals in the International System of Units (SI). Many techniques have been developed for the measurement of pressure and vacuum. Instruments used to measure and display pressure mechanically are called pressure gauges, vacuum gauges or compound gauges (vacuum & pressure). The widely used Bourdon gauge is a mechanical device, which both measures and indicates and is probably the best known type of gauge. A vacuum gauge is used to measure pressures lower than the ambient atmospheric pressure, which is set as the zero point, in negativ…

Evidence: 45 • authority: 72

The mercury-in-glass or mercury thermometer is a thermometer that uses the thermal expansion and contraction of liquid mercury to indicate the temperature.