Ms. Leah McEwen is an active leader in the professional chemical information community. She has supported research and learning communities in chemistry and related fields at Cornell University where she was the Chemistry Library for over 26 years. She has also served in numerous roles and leadership positions in the International Union of Pure and Applied Chemistry (IUPAC), the American Chemical Society (ACS), and the Research Data Alliance (RDA). She has extensive experience in preparation and management of scientific research outputs and an appreciation of the value and requirements for accurate documentation and metadata necessary to identify, access and reuse data. She is familiar with information workflows and needs across a range of scientific fields in diverse sectors.Ms. McEwen is internationally recognized for connecting people around common information challenges in digital data and scientific communication. She has organized dozens of topical symposia, workshops and collaborations with researchers, educators, policymakers, funders, publishers, software developers, scientific societies, federal agencies, government labs, industry groups, private institutes, and global organizations worldwide. She has collaborated with many institutes and initiatives on developing workflows and services for managing scientific data, including the International Science Council Committee on Data (CODATA), the Commission for Isotopic Abundances and Atomic Weights (CIAAW), the Beilstein-Institut, the Pistoia Alliance of pharmaceutical companies, the US National Center for Biotechnology Information, European Bioinformatics Institute, and several national level research data infrastructure initiatives.Ms. McEwen has been mobilizing the chemical information community around the development of chemical data standards for over a decade. She is an active contributor to many digital standards projects and initiatives, including the International Chemical Identifier (InChI), the Gold Book Compendium of Chemical Terminology, the IUPAC critical evaluation of data program, and the WorldFAIR data reproducibility initiative. She had contributed to guidance and instruction materials on chemical data standards and standardized data reporting and evaluation that are accessed worldwide. She has also been involved in several initiatives to promote chemical safety and the use of chemical data for assessing and managing risk in academic research and teaching laboratories. She is a codeveloper and curator of the Laboratory Chemical Safety Summary data stream from the PubChem database at the NIH to facilitate public access to authoritative chemical safety data.

• Section 0: IntroductionThe Editor and Editorial BoardPrefaceNew Data and Updates in the 107th EditionOn the Evaluation of Chemistry and Physics DataCurrent ContributorsPart 1 Data on Chemical SubstancesSection 1: Elements and Their IsotopesIntroductionThe Elements: PropertiesStandard Atomic WeightsAtomic Masses and Isotopic AbundancesAbundance of Elements in the Earth's Crust and in the SeaMelting, Boiling, Triple, and Critical Points and Densities of the ElementsHeat Capacity of the Elements at 25 °CHeat Capacity of Solid Elements as a Function of TemperatureTable of the IsotopesPhase Transition Temperatures of the Solid Elements at Atmospheric PressureCrystal Structures and Lattice Parameters of Allotropes of the ElementsDensity of Molten Elements as a Function of TemperaturePhysical and Thermal Properties of Rare-Earth MetalsThermal Properties of Pure Elemental MetalsElectrical Resistivity of Pure Elemental MetalsElectron Work Function of the ElementsMagnetic Susceptibility of the ElementsOptical Properties of The ElementsElectronegativity of the ElementsIndex of Refraction of Liquid ElementsVapor Pressure of the Metallic ElementsThe Elements: Description and HistorySection 2: Atomic Structure and Spectroscopy DataIntroductionElectron Configuration and Ionization Energies of Neutral Atoms and Atomic IonsElectron Affinities of the Atomic ElementsPersistent Lines of the Neutral Atomic ElementsAtomic Radii of the ElementsPolarizabilities of the Atomic ElementsSection 3: Properties of Organic CompoundsIntroductionPhysical Constants of Organic CompoundsCAS Registry Number Index of Organic CompoundsDiamagnetic Susceptibility of Organic CompoundsCritical Constants of Organic CompoundsDissociation Constants of Organic Acids and BasesMiscibility of Organic SolventsDependence of Boiling Point of Organic Liquids on PressureBond Lengths in Crystalline Organic CompoundsBond Lengths in Organometallic CompoundsPerfluoro- and Polyfluoroalkyl SubstancesSection 4: Properties of Inorganic CompoundsIntroductionPhysical Constants of Inorganic CompoundsCAS Registry Number Index of Inorganic CompoundsCritical Constants of Inorganic CompoundsPermittivity (Dielectric Constant) of Inorganic SolidsDensity of Molten Inorganic Salts as a Function of TemperatureDissociation Constants of Inorganic Acids and BasesIndex of Refraction of Inorganic LiquidsIndex of Refraction of Inorganic CrystalsMagnetic Susceptibility of Inorganic CompoundsOptical Properties of Inorganic SolidsAqueous Solubility of Inorganic Compounds as a Function of TemperatureSolubility Product Constants of Inorganic SaltsSolubility Charts for Inorganic SaltsTransition Temperatures and Heats of Transitions for Metal SaltsProperties of Gas Clathrate HydratesPhysical and Optical Properties of MineralsCrystallographic Data on MineralsSection 5: Properties of WaterIntroductionThermophysical Properties of Water and SteamFixed-Point Thermophysical Properties of H2O and D2OProperties of Saturated Liquid D2OVapor Pressure and Other Saturation Properties of WaterStandard Density of Water as a Function of TemperatureIonization Constant of Water as a Function of Temperature and PressureIonization Constant of Normal and Heavy Water at Saturated Vapor PressureElectrical Conductivity of WaterPermittivity (Dielectric Constant) of Water as a Function of FrequencyProperties of Ice and Supercooled WaterVapor Pressure of IceSolid-Liquid Phase Equilibria for Ice as a Function of PressureIndex of Refraction of WaterProperties of SeawaterSolubility of Hydrocarbons in SeawaterSection 6: Properties of PolymersIntroductionPhysical Properties of Important PolymersPolymer SolventsGlass Transition Temperatures for PolymersPermittivity of PolymersPressure-Volume-Temperature Relationships for Polymer MeltsVapor Pressures (Solvent Activities) for Binary Polymer SolutionsSolubility Parameters of PolymersSection 7: Properties of Bio-Medical Compounds and SubstancesIntroductionProperties of Amino AcidsStructures of Amino AcidsProperties of Purine and Pyrimidine BasesThe Genetic CodeProperties of Fatty Acids and their Methyl EstersComposition and Properties of Oils and FatsStandard Transformed Gibbs Energies of Formation for Biochemical ReactantsApparent Equilibrium Constants for Enzyme-Catalyzed ReactionsApparent Equilibrium Thermodynamics of Protein-Ligand Binding ReactionsThermodynamic Quantities for the Ionization Reactions of Buffers in WaterBiological BufferspH Values of Biological Materials and FoodsProperties and Functions of Important DrugsProperties of Controlled SubstancesSection 8: Chemical Structure, Bonding, and Molecular Spectroscopy DataIntroductionStructure of Free Molecules in the Gas PhaseCharacteristic Bond Lengths in Free MoleculesDipole MomentsHindered Internal RotationBond Dissociation EnergiesForce Constants for Bond StretchingFundamental Vibrational Frequencies of Small MoleculesSpectroscopic Constants of Diatomic MoleculesPolarizabilities of MoleculesIonization Energies of Gas-Phase MoleculesElectron Affinities of MoleculesPart 2 Data for the Practice of Chemistry and PhysicsSection 9: Physical Chemistry DataIntroductionCODATA Key Values for ThermodynamicsStandard Thermodynamic Properties of Chemical SubstancesThermodynamic Properties as a Function of TemperatureThermodynamic Properties of Aqueous IonsProton AffinitiesHeat of CombustionHeat Capacity of Solids as a Function of TemperatureTransition Temperatures And Heats of Transition for Metal Oxyanion SaltsElectrical Conductivity of Aqueous SolutionsMolar Electrical Conductivity of Aqueous HF, HCl, HBr, and HIMolar Electrical Conductivity of Electrolytes in Aqueous SolutionIonic Conductivity and Diffusion at Infinite DilutionElectrochemical SeriesMean Activity Coefficients of Acids, Bases, and Salts as a Function of ConcentrationEnthalpy of Dilution of AcidsEnthalpy of Solution of ElectrolytesConcentrative Properties of Aqueous SolutionsEbullioscopic Constants for Calculation of Boiling Point ElevationCryoscopic Constants for Calculation of Freezing Point DepressionFreezing Point Lowering by Electrolytes in Aqueous SolutionAzeotropic Data for Binary MixturesSection 10: Environmental Chemistry DataIntroductionChemical Reaction Rate Constants for Atmospheric StudiesProperties of RefrigerantsGlobal Warming Potential of Greenhouse GasesAir-Broadened Infrared Absorption Cross Sections for Greenhouse GasesAnnual Atmospheric Concentration of Carbon Dioxide and MethaneAqueous Solubility and Henry's Law Constants of Organic CompoundsOctanol-Water Partition CoefficientsGlobal Temperature Trend, 1880-2024Solar Irradiance at the EarthGeographical and Seasonal Variations in Solar RadiationInfrared Absorption by the Earth's AtmosphereU.S. Standard Atmosphere (1976)Section 11: Solid-State Chemistry and Physics DataIntroductionThermal Analysis for Materials CharacterizationMicroscopy Techniques for Materials CharacterizationSymmetry of CrystalsIonic Radii in CrystalsThe Madelung Constant and Crystal Lattice EnergyElastic Constants of Single CrystalsPolarizabilities of Atoms and Ions in SolidsElectrical Resistivity of Binary AlloysElectrical Resistivity of Carbon MaterialsCurie Temperature of Ferroelectric CrystalsProperties of Antiferroelectric CrystalsProperties of SuperconductorsHigh-Temperature SuperconductorsOrganic SuperconductorsProperties of SemiconductorsProperties of Semiconductor Solid SolutionsProperties of Organic SemiconductorsDiffusion Data for SemiconductorsProperties of Magnetic MaterialsOrganic MagnetsThermal and Strength Properties of Materials at Cryogenic TemperaturesThermoelectric Properties of Metals and SemiconductorsThermal Conductivity of Metals and Semiconductors as a Function of TemperatureFermi Energy and Related Properties of MetalsSecondary Electron EmissionElectron Inelastic Mean Free PathsElectron Stopping PowersAttenuation Coefficients for High-Energy Electromagnetic RadiationThermal Conductivity of Crystalline DielectricsThermal Conductivity of Ceramics and Other Insulating MaterialsCoefficient of FrictionSection 12: Industrial Chemistry DataIntroductionThermophysical Properties of AirThermophysical Properties of FluidsThermophysical Properties of Fluids at SaturationVapor Pressure of Compounds and ElementsVapor Pressure of Fluids at Temperatures below 300 KVapor Pressure of Saturated Salt SolutionsEnthalpy of Vaporization of Compounds and ElementsEnthalpy of Fusion of Compounds and ElementsVirial Coefficients of GasesCompressibility and Expansion Coefficients of LiquidsTemperature and Pressure Dependence of Liquid DensityProperties of Cryogenic FluidsProperties of Liquid HeliumProperties of Ionic LiquidsEnergy Content of FuelsSurface Tension of LiquidsSurface Tension of Aqueous MixturesSurface Active Chemicals (Surfactants)Permittivity (Dielectric Constant) of LiquidsPermittivity (Dielectric Constant) of GasesViscosity of GasesViscosity of LiquidsThermal Conductivity of Gases and RefrigerantsThermal Conductivity of LiquidsInfluence of Pressure on Freezing PointsSublimation Pressure of SolidsSolubility of Gases in Water as a Function of TemperatureSolubility of Carbon Dioxide in Water as a Function of Temperature and PressureSolubility of Organic Compounds in Pressurized Hot WaterDiffusion in GasesDiffusion of Gases in WaterDiffusion Coefficients in Liquids at Infinite DilutionMean Free Path and Related Properties of GasesIndex of Refraction of AirIndex of Refraction of GasesIndex of Refraction of Liquids for Calibration PurposesSection 13: Astrophysics, Earth Sciences, and Physics DataIntroductionAstronomical ConstantsProperties of the Solar SystemInterstellar MoleculesMass, Dimensions, and Other Parameters of the EarthDensity, Pressure, and Gravity as a Function of Depth within the EarthAcceleration Due to GravityOcean Pressure as a Function of Depth and LatitudeSummary Tables of Particle PropertiesBlackbody RadiationClassification of Electromagnetic RadiationPart 3 Data for Modern Chemical LaboratoriesSection 14: Analytical Chemistry DataIntroductionBasic Instrumental Techniques of Analytical ChemistryAnalytical Standardization and CalibrationProperties of Carrier Gases for Gas ChromatographyDetectors for Gas ChromatographyStationary Phases for Open Tubular ColumnsPhase Ratios for Capillary ColumnsSolid-Phase Microextraction SorbentsCryotrapping CoolantsHPLC PreparationDetectors for Liquid ChromatographySolvents for Ultraviolet SpectrophotometryCorrelation Table for Ultraviolet Active FunctionalitiesMiddle-Range Infrared Absorption Correlation ChartsOrganic Analytical Reagents for the Determination of Inorganic IonsRaman Band FrequenciesNuclear Spins, Moments, and Other Data Related to NMR SpectroscopyProton NMR Absorption of Major Chemical FamiliesProton NMR Correlation Chart for Major Organic Functional GroupsProton NMR Shifts of Organic Liquids13C-NMR Absorptions of Major Functional Groups13C-NMR Chemical Shifts of Organic Solvents15N-NMR Chemical Shifts of Major Chemical FamiliesNatural Abundance of Isotopes Important in Mass SpectrometryMass Spectral Fragmentation Patterns of Organic Compound FamiliesReference Masses in the Spectrum of Heptacosafluorotributylamine (Perfluorotributylamine)Mass Spectral Peaks of Organic LiquidsSpurious Signals Observed in Mass SpectrometersChlorine-Bromine Combination Isotope Intensities in Mass Spectral PatternsX-Ray Fluorescence Spectroscopy TechniquesSection 15: Practical Laboratory DataIntroductionLaboratory Solvents and Other Liquid ReagentsDensity of Solvents as a Function of TemperaturepH Scale for Aqueous SolutionsBuffer Solutions Giving Round Values of pH at 25 °CConstant Humidity SolutionsLow-Temperature Baths for Maintaining Constant TemperatureMetals and Alloys with Low-Melting TemperatureStandard KCl Solutions for Calibrating Electrical Conductivity CellsCharacteristics of Particles and Particle DispersoidsInternational Temperature Scale of 1990 (ITS-90)Reference Points on the ITS-90 Temperature ScaleRecommended Secondary Reference Points on the International Temperature Scale of 1990 (ITS-90)Standard ITS-90 Thermocouple TablesMetal Carbide-Carbon Phase Transition TemperaturesSection 16: Chemical and Laboratory Safety DataIntroductionChemical Safety in LaboratoriesLaboratory Risk AssessmentIncompatible ChemicalsWater-Reactive and Pyrophoric Chemical HazardsPeroxide TestingShock and Friction Sensitive HazardsFlammable Liquids Categorization CriteriaFlammability of Solvents and Other Chemical SubstancesChemical CarcinogensIonizing Radiation HazardsAnnual Limits on Intakes of RadionuclidesSafety in the Use of CryogensNanomaterial Safety GuidelinesExposure & Toxicity LimitsThreshold Limits for Airborne ContaminantsChemical Fume Hoods and Biological Safety CabinetsCompressed Air SafetyLaser Hazards in the LaboratoryNonionizing Radiation SafetyElectrical Equipment HazardsLaboratory GlovesProtective ClothingRespirator Cartridges and FiltersHearing Protection DevicesFire ExtinguishersPart 4 Reference Tables and IndicesSection 17: Quantities, Units, Constants, and Conversion FactorsIntroductionCODATA Recommended Values of the Fundamental Physical Constants: 2018International System of Units (SI)Expression of Uncertainty of MeasurementsFigures of MeritSymbols and Terminology for Physical and Chemical QuantitiesMass- and Volume-Based Concentration UnitsUnits for Magnetic PropertiesRadiation UnitsConversion Factors for Energy UnitsUnits and Conversion Factors for Pressure and Vacuum SystemsValues of the Gas Constant in Different Unit SystemsConversion Factors for Thermal Conductivity UnitsThermodynamic Functions and RelationsMass- and Volume-Based Concentration UnitsSection 18: Chemical Representation and NomenclaturIntroductionNomenclature for Chemical CompoundsGraphical representationCarbohydrate Names and SymbolsSection 19: Abbreviations and Terminology Glossary of abbreviations and concepts used in the CRC HandbookSection 20: Covers and IndicesPeriodic Table of the ElementsStandard Atomic Weights in Atomic Order NumberFundamental Physical Constants - Frequently Used Constants