stewart_1991
============

R\. B\. Stewart, R\. T Jacobsen and W\. Wagner, "Thermodynamic Properties of Oxygen from the Triple Point to 300 K with Pressures to 80 MPa", J\. Phys\. Chem\. Ref\. Data 20, 917 \(1991\)

`Source record <https://github.com/LupoLab/optmat/blob/main/src/optmat/data/sources/stewart_1991.toml>`__ · :doc:`Catalogue </the-data/sources>` · :doc:`Review register </register>`

DOI: `10\.1063/1\.555897 <https://doi.org/10.1063/1.555897>`__

**Source kind:** fit

**Recorded technique:** Tables of the thermodynamic properties of oxygen from Schmidt and Wagner's fundamental equation, with its ideal\-gas part, ancillary equations and comparisons with the data, from the freezing line to 300 K at pressures to 80 MPa\.

**Materials in structured entries:** O2

**Dataset quantities:** None recorded.

**Contents:** 0 datasets; 1 formula.

Curation notes
--------------

Identity VALIDATED\_WITH\_WARNINGS by the library\. Pages cited are pdf pages\.

IDEAL GAS \(section 4, pdf p\. 11\)\: R = 8\.31434 J/\(mol K\), M = 31\.9988 g/mol \(pdf p\. 4\)\. Eq\. \(11\), Wagner, Ewers and Schmidt's equation, is the one Schmidt and Wagner \(1985\) use\: c\_p0/R = N1 T^\-1\.5 \+ N2 \+ N3 T^2 \+ N4 u^2 e^u/\(e^u \- 1\)^2 \+ N5 \(2/3\) eta^2 e^\-eta/\[1 \+ \(2/3\) e^\-eta\]^2, u = N6/T, eta = N7/T, with N1\.\.N7 = 1\.06778, 3\.50042, 0\.166961e\-7, 1\.01258, 0\.944365, 2242\.45, 11580\.4\. It was fitted to Baehr et al\.'s values \(30\-1100 K\) and Gurvich et al\.'s \(100\-3000 K\), which it meets within 0\.003 J/\(mol K\)\. Eq\. \(12\), Stewart and Jacobsen's earlier equation, is given as an alternative for 70\-1100 K \(0\.002 J/\(mol K\)\)\.

AGAINST COOLPROP 8\.0\.0 \(reference key Schmidt\-FPE\-1985, Stewart\-JPCRD\-1991, computed 2026\-09\-30\)\: CoolProp's ideal part is a refit of Eq\. \(11\)\. The two agree to 3\.3e\-6 from 60 K to 1500 K, then part\: \-1\.6e\-5 at 1600 K, \-4\.9e\-5 \(\-0\.0018 J/\(mol K\)\) at 1700 K, \-1\.1e\-4 at 1800 K and \-3\.5e\-4 \(\-0\.013 J/\(mol K\)\) at 2000 K, beyond Eq\. \(11\)'s 0\.003 J/\(mol K\) from 1800 K\. optmat's O2 heat capacity therefore stops at 1700 K \(TC\-765\)\. Against Eq\. \(12\) CoolProp differs by up to 1\.5e\-4 at 60\-1000 K\.

**Recorded bibliographic identity status:** VALIDATED\_WITH\_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.

Datasets
--------

No datasets are recorded.

Formulas
--------

stewart\_1991/eq11
~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "eq11",
     "material": "O2",
     "equation": "Eq. (11), pdf p. 11",
     "printed": "c_p0/R = N1 T^-1.5 + N2 + N3 T^2 + N4 u^2 e^u/(e^u - 1)^2 + N5 (2/3) eta^2 e^-eta/[1 + (2/3) e^-eta]^2",
     "variable": "u = N6/T, eta = N7/T, T in K",
     "range": "30-3000 K (its fit)",
     "coefficients": {
       "N1": "1.06778",
       "N2": "3.50042",
       "N3": "0.166961e-7",
       "N4": "1.01258",
       "N5": "0.944365",
       "N6": "2242.45",
       "N7": "11580.4"
     },
     "check": "CoolProp 8.0.0's refit agrees to 3.3e-6 from 60 K to 1500 K (tests/test_transport.py)."
   }

Corrections
-----------

No dataset errata are recorded in this source record.

Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the :doc:`review register </register>` for the checks and decisions.