Compound Information 

Name: pyrazine
Formula: C4H4N2
Molar Mass: 80.09
Additional Names: 1,4-diazine
Image of pyrazine

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Property Availability 

For this compound, WTT contains critically evaluated recommendations for:
(Please note that if more than 50 points are used for regression, only the 50 most-constraining points are reported)

  • Triple point temperature
    • Triple point temperature (Crystal 3, Crystal 2, and Gas)
      4 experimental data points
    • Triple point temperature (Crystal 2, Crystal 1, and Gas)
      3 experimental data points
    • Triple point temperature (Crystal 1, Liquid, and Gas)
      5 experimental data points
    • Triple point temperature (Crystal 4, Crystal 3, and Gas)
      1 experimental data points
  • Normal boiling temperature (Liquid and Gas)
    • Critical temperature (Liquid and Gas)
      1 experimental data points
      • Critical pressure (Liquid and Gas)
        • Boiling temperature (Liquid in equilibrium with Gas) as a function of Pressure
          Pressure from 31.1894 kPa to 6480.81 kPa
          • Phase boundary pressure (Liquid in equilibrium with Gas) as a function of Temperature
            Temperature from 353.704 K to 627 K
            16 experimental data points
            • Critical density (Liquid and Gas)
              • Density
                • Density (Liquid in equilibrium with Gas) as a function of Temperature
                  Temperature from 325.445 K to 627 K
                  12 experimental data points
                • Density (Gas in equilibrium with Liquid) as a function of Temperature
                  Temperature from 503.227 K to 627 K
                  2 experimental data points
                • Density (Gas) as a function of Temperature and Pressure
                  Temperature from 310 K to 620 K
                  Pressure from 0.001 kPa to 1238.58 kPa
              • Enthalpy of phase transition
                • Enthalpy of phase transition (Crystal 4 to Crystal 3 in equilibrium with Gas)
                  1 experimental data points
                • Enthalpy of phase transition (Crystal 3 to Crystal 2 in equilibrium with Gas)
                  4 experimental data points
                • Enthalpy of phase transition (Crystal 2 to Crystal 1 in equilibrium with Gas)
                  3 experimental data points
                • Enthalpy of phase transition (Crystal 1 to Liquid in equilibrium with Gas)
                  2 experimental data points
              • Enthalpy of vaporization or sublimation (Liquid to Gas) as a function of Temperature
                Temperature from 325.445 K to 627 K
                • Heat capacity at saturation pressure
                  • Heat capacity at saturation pressure (Crystal 4 in equilibrium with Gas) as a function of Temperature
                    Temperature from 0.0001 K to 95.7 K
                    50 experimental data points
                  • Heat capacity at saturation pressure (Crystal 2 in equilibrium with Gas) as a function of Temperature
                    Temperature from 300.53 K to 309.8 K
                    13 experimental data points
                  • Heat capacity at saturation pressure (Crystal 1 in equilibrium with Gas) as a function of Temperature
                    Temperature from 309.8 K to 325.445 K
                    16 experimental data points
                  • Heat capacity at saturation pressure (Liquid in equilibrium with Gas) as a function of Temperature
                    Temperature from 325.445 K to 614.46 K
                    26 experimental data points
                  • Heat capacity at saturation pressure (Crystal 3 in equilibrium with Gas) as a function of Temperature
                    Temperature from 95.7 K to 300.53 K
                    50 experimental data points
                • Heat capacity at constant pressure (Ideal Gas) as a function of Temperature
                  Temperature from 298 K to 1000 K
                  • Enthalpy
                    • Enthalpy (Crystal 4 in equilibrium with Gas) as a function of Temperature
                      Temperature from 0.0001 K to 95.7 K
                    • Enthalpy (Crystal 3 in equilibrium with Gas) as a function of Temperature
                      Temperature from 95.7 K to 300.53 K
                    • Enthalpy (Crystal 2 in equilibrium with Gas) as a function of Temperature
                      Temperature from 300.53 K to 309.8 K
                    • Enthalpy (Crystal 1 in equilibrium with Gas) as a function of Temperature
                      Temperature from 309.8 K to 325.445 K
                    • Enthalpy (Liquid in equilibrium with Gas) as a function of Temperature
                      Temperature from 325.445 K to 614.46 K
                    • Enthalpy (Ideal Gas) as a function of Temperature
                      Temperature from 298 K to 1000 K
                  • Entropy
                    • Entropy (Crystal 4 in equilibrium with Gas) as a function of Temperature
                      Temperature from 0.0001 K to 95.7 K
                      11 experimental data points
                    • Entropy (Crystal 3 in equilibrium with Gas) as a function of Temperature
                      Temperature from 95.7 K to 300.53 K
                      24 experimental data points
                    • Entropy (Crystal 2 in equilibrium with Gas) as a function of Temperature
                      Temperature from 300.53 K to 309.8 K
                      6 experimental data points
                    • Entropy (Crystal 1 in equilibrium with Gas) as a function of Temperature
                      Temperature from 309.8 K to 325.445 K
                      6 experimental data points
                    • Entropy (Liquid in equilibrium with Gas) as a function of Temperature
                      Temperature from 325.445 K to 614.46 K
                      7 experimental data points
                    • Entropy (Ideal Gas) as a function of Temperature and Pressure
                      Temperature from 298 K to 1000 K
                  • Refractive index (Liquid) as a function of Wavelength, Temperature, and Pressure
                    Wavelength from 434.05 nm to 670.779 nm
                    Temperature from 334.024 K to 339.224 K
                    8 experimental data points
                    • Viscosity (Gas) as a function of Temperature and Pressure
                      Temperature from 390 K to 940 K
                      • Thermal conductivity (Gas) as a function of Temperature and Pressure
                        Temperature from 390 K to 940 K
                        • Enthalpy of formation (Crystal)
                          1 experimental data points

                          About WTT 

                          NIST/TRC Web Thermo Tables (WTT)
                          NIST Standard Reference Subscription Database 3 - Professional Edition
                          Version 2-2012-1-Pro

                          This web application provides access to a collection of critically evaluated thermodynamic property data for pure compounds with a primary focus on organics. These data were generated through dynamic data analysis, as implemented in the NIST ThermoData Engine software package [1, 2, 3, 4, 5, 6]. Some critically evaluated data from the historical TRC Thermodynamic Tables archive [7, 8] are included, also. As of May 2012, the Professional Edition contains information on 28432 compounds and total of 531486 evaluated data points. The properties covered by both versions (32 total) are described in Properties and Implemented Models.

                          Developed by Kenneth Kroenlein, Chris D. Muzny, Andrei F. Kazakov, Vladimir Diky, Robert D. Chirico, Joseph W. Magee, Ilmutdin Abdulagatov and Michael Frenkel.

                          Thermodynamics Research Center (TRC)
                          Thermophysical Properties Division
                          National Institute of Standards and Technology
                          Boulder CO 80305-3337

                          Questions and comments should be addressed to Dr. Michael Frenkel .

                          DISCLAIMER: The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high-quality copy of the database and to verify that the methods and data contained therein have been selected on the basis of sound scientific judgement. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the program and database.

                          Distributed by:
                          Standard Reference Data Program
                          National Institute of Standards and Technology
                          Gaithersburg MD 20899

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