blancett_1970#
A. L. Blancett, K. R. Hall and F. B. Canfield, “Isotherms for the He-Ar system at 50°C, 0°C and -50°C up to 700 atm”, Physica 47, 75 (1970)
Source record · Catalogue · Review register
DOI: 10.1016/0031-8914(70)90101-1
Source kind: measurement
Recorded technique: Burnett expansion method (pp. 75-81): a pressure-jacketed Monel K-500 cell of two volumes (about 80 and 160 cc) in a gas-bath cryostat, with a gas circulating pump, and two diaphragm pressure-null indicators in series (one inside the cryostat) between the gas and Ruska piston gauges (to 165 and 700 atm), corrected for head, barometric pressure and the indicators’ zero shifts. Temperature by a capsule platinum resistance thermometer in the larger volume on IPTS-48; steady gradients in the cell 0.012, 0.015 and 0.03 K at -50, 0 and +50 °C. Two runs per composition and isotherm, from 3 to 700 atm. Data reduced by the method of Hall and Canfield (Physica 47, 99 (1970)), which fits the Burnett constants and a virial series in density simultaneously by least squares, the number of virial terms chosen by the data, with weights proportional to (3 + P)^-2. Helium, argon and four mixtures of 21.99, 41.05, 59.35 and 80.00 mole percent helium, the compositions recommended from mass-spectrographic and molecular-weight analyses (p. 81).
Materials in structured entries: Ar, He
Dataset quantities: mixture_compressibility_factor, mixture_second_virial_coefficient, second_virial_coefficient
Contents: 18 datasets; 0 formulas.
Curation notes#
Identity VALIDATED_WITH_WARNINGS by the library (bibliography VALIDATED; Crossref fields). Printed pp. 75-91 (pdf pages 1-17; printed page = pdf page + 74). Received 28 July 1969.
TABLE I (pp. 82-87; Compressibility factors): for helium, the four mixtures and argon, two runs at 323.15, 273.15 and 223.15 K, each row the observed pressure P (atm), Z = Pv/RT and sigma(Z) x 10^5. The text (p. 90) says these are ‘the compressibility factors (as calculated from the virial coefficients) vs. the observed pressure’: each Z is the fitted virial series of Table II at the observed pressure, not a raw Burnett value, and the Z of one isotherm are therefore correlated. Extracted: the four mixtures’ Z up to 150 atm (the cut; optmat’s domain is below about 100 bar), one dataset per composition and temperature, 198 values; the rows above 150 atm (to 713 atm) are left in the table. The pure-helium and pure-argon isotherms are not extracted: optmat takes the pure gases from their reference equations of state.
THE LIBRARY COPY IS CLIPPED. The scan cuts the long edges of the landscape pages (checked on the table crops and 300-1200 dpi renderings, 2026-10-01). Pages 83, 85 and 87 have lost their composition labels; p. 82 shows one more row cut through below 12.3080 atm, and p. 85 a row cut through above 380.141 atm. On the labelled pages the first run starts near 700 atm and the second ends near 3 atm; on the clipped edges the first runs of pp. 83 and 85 start near 400 atm and the second runs of pp. 82, 84 and 86 stop near 12 atm. So the highest-pressure row of the first runs of 80.00 % and 41.05 % helium (above the cut), and the rows below about 12 atm of the second runs of helium, 59.35 % and 21.99 % helium (within it), are very probably missing from this copy; a complete copy of pp. 82-88 should be sought. The extraction script sets the compositions of the unlabelled pages (p. 83 80.00 % helium, p. 85 41.05 % helium, p. 87 argon), which the reproduction below establishes.
CHECKED (2026-10-01): every extracted cell (P, Z and sigma, 198 rows) against the table images; they agree. Every printed Z up to 150 atm is reproduced from the Table II virial series of its composition and temperature, Z = 1 + sum_k B_k rho^(k-1) solved for rho at the printed P with R = 82.057 cm^3 atm/(mol K): within 1.0e-5 (one unit of the last printed digit; rms 0.3e-5) for all 198 values of the mixtures, and within 0.9e-5 for helium and 5.7e-5 for argon. Any other composition’s series misses the same rows by at least 9e-3. The result is insensitive to R between 82.056 and 82.06.
TABLE II (p. 88; Virial coefficients, (cc/g mol)^(k-1)): for each composition and temperature the coefficients B_k of Z = 1 + B_2 rho + B_3 rho^2 + ..., k = 2 to 4-7 as the data required, with sigma(B_k). Extracted: B_2 of the mixtures (mixture_second_virial_coefficient) and of helium and argon (second_virial_coefficient), checked against the page image. Not extracted: B_3 and higher, for which the vocabulary has no quantity (they are recorded here only as needed to reproduce Table I: the scripts’ library tables hold them). Several sigma cells end in a printed period (‘0.0925.’, ‘455.’), dropped from the number.
THE INTERACTION COEFFICIENT B_HeAr (p. 90, Eq. 1): the authors fitted B = x_He^2 B_He + 2 x_He x_Ar B_HeAr + x_Ar^2 B_Ar to the B_2 of helium, argon and the four mixtures, weighted by 1/sigma(B)^2, and printed B_HeAr at each temperature as the last row of Table II. In the library copy that row is cut through by the page edge: only the tops of the characters remain, readable as 18.4.., 17.5.. and 16.0.. cm^3/mol, and no value is extracted. Refitting Eq. (1) as described to the printed B_2 gives B_HeAr = 18.48, 17.59 and 16.07 cm^3/mol at 323.15, 273.15 and 223.15 K (B_He and B_Ar fitted too; with them fixed at their printed values, 18.50, 17.56 and 16.24), consistent with the visible leading digits. The printed values should be read from a complete copy.
TABLES III and IV (p. 89): the Burnett cell constants N_inf, run constants Z_0/P_0 and pressure-distortion coefficients, with Eq. (2)-(3) to recompute Z from the observed pressures. Apparatus constants, not extracted.
UNCERTAINTY: ‘The tabulated standard deviations have all been estimated from a propagation of errors analysis’ (p. 90): sigma(Z) from 0.06 % at the highest pressures to 0.001 % at the lowest, about 0.3 % for B_2 and 2 % for B_3. Taken as one standard deviation. A printed sigma(Z) of 0 (some rows near 3 atm) means below 0.5e-5 after rounding; it is kept as printed (0e-5), and a fit should floor it. The compositions’ uncertainty is not stated. The paper’s ‘A at -50 °C has some unusually high deviations’ (p. 90) refers to argon’s 223.15 K isotherm (sigma(Z) up to 294e-5 at 489 atm), which is not extracted.
TEMPERATURES are as printed (323.15, 273.15 and 223.15 K), measured on IPTS-48; the difference from ITS-90 at these temperatures (a few mK) is below the stated gradients.
Recorded bibliographic identity status: VALIDATED_WITH_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.
Datasets#
blancett_1970/Z_xAr_0.2000_323.15K#
{
"id": "Z_xAr_0.2000_323.15K",
"material": "Ar",
"file": "Ar/blancett_1970__Z_xAr_0.2000_323.15K.csv",
"table": "tbl_63fcad0741b0",
"quantity": "mixture_compressibility_factor",
"abscissa": "pressure",
"abscissa_unit": "atm",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.2,
"temperature_k": 323.15
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table I (p. 83; composition label clipped, set by the script): Z = Pv/RT of 80.00 mole percent helium in argon at 323.15 K against the observed pressure, both runs, P <= 150 atm; Z is the fitted virial series at the observed pressure (record notes). x_Ar = 1 - x_He.
blancett_1970/Z_xAr_0.2000_273.15K#
{
"id": "Z_xAr_0.2000_273.15K",
"material": "Ar",
"file": "Ar/blancett_1970__Z_xAr_0.2000_273.15K.csv",
"table": "tbl_63fcad0741b0",
"quantity": "mixture_compressibility_factor",
"abscissa": "pressure",
"abscissa_unit": "atm",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.2,
"temperature_k": 273.15
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table I (p. 83; composition label clipped, set by the script): Z = Pv/RT of 80.00 mole percent helium in argon at 273.15 K against the observed pressure, both runs, P <= 150 atm; Z is the fitted virial series at the observed pressure (record notes). x_Ar = 1 - x_He.
blancett_1970/Z_xAr_0.2000_223.15K#
{
"id": "Z_xAr_0.2000_223.15K",
"material": "Ar",
"file": "Ar/blancett_1970__Z_xAr_0.2000_223.15K.csv",
"table": "tbl_63fcad0741b0",
"quantity": "mixture_compressibility_factor",
"abscissa": "pressure",
"abscissa_unit": "atm",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.2,
"temperature_k": 223.15
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table I (p. 83; composition label clipped, set by the script): Z = Pv/RT of 80.00 mole percent helium in argon at 223.15 K against the observed pressure, both runs, P <= 150 atm; Z is the fitted virial series at the observed pressure (record notes). x_Ar = 1 - x_He.
blancett_1970/Z_xAr_0.4065_323.15K#
{
"id": "Z_xAr_0.4065_323.15K",
"material": "Ar",
"file": "Ar/blancett_1970__Z_xAr_0.4065_323.15K.csv",
"table": "tbl_44bf2fa88c63",
"quantity": "mixture_compressibility_factor",
"abscissa": "pressure",
"abscissa_unit": "atm",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.4065,
"temperature_k": 323.15
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table I (p. 84): Z = Pv/RT of 59.35 mole percent helium in argon at 323.15 K against the observed pressure, both runs, P <= 150 atm; Z is the fitted virial series at the observed pressure (record notes). x_Ar = 1 - x_He.
blancett_1970/Z_xAr_0.4065_273.15K#
{
"id": "Z_xAr_0.4065_273.15K",
"material": "Ar",
"file": "Ar/blancett_1970__Z_xAr_0.4065_273.15K.csv",
"table": "tbl_44bf2fa88c63",
"quantity": "mixture_compressibility_factor",
"abscissa": "pressure",
"abscissa_unit": "atm",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.4065,
"temperature_k": 273.15
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table I (p. 84): Z = Pv/RT of 59.35 mole percent helium in argon at 273.15 K against the observed pressure, both runs, P <= 150 atm; Z is the fitted virial series at the observed pressure (record notes). x_Ar = 1 - x_He.
blancett_1970/Z_xAr_0.4065_223.15K#
{
"id": "Z_xAr_0.4065_223.15K",
"material": "Ar",
"file": "Ar/blancett_1970__Z_xAr_0.4065_223.15K.csv",
"table": "tbl_44bf2fa88c63",
"quantity": "mixture_compressibility_factor",
"abscissa": "pressure",
"abscissa_unit": "atm",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.4065,
"temperature_k": 223.15
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table I (p. 84): Z = Pv/RT of 59.35 mole percent helium in argon at 223.15 K against the observed pressure, both runs, P <= 150 atm; Z is the fitted virial series at the observed pressure (record notes). x_Ar = 1 - x_He.
blancett_1970/Z_xAr_0.5895_323.15K#
{
"id": "Z_xAr_0.5895_323.15K",
"material": "Ar",
"file": "Ar/blancett_1970__Z_xAr_0.5895_323.15K.csv",
"table": "tbl_4f20e52886e0",
"quantity": "mixture_compressibility_factor",
"abscissa": "pressure",
"abscissa_unit": "atm",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.5895,
"temperature_k": 323.15
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table I (p. 85; composition label clipped, set by the script): Z = Pv/RT of 41.05 mole percent helium in argon at 323.15 K against the observed pressure, both runs, P <= 150 atm; Z is the fitted virial series at the observed pressure (record notes). x_Ar = 1 - x_He.
blancett_1970/Z_xAr_0.5895_273.15K#
{
"id": "Z_xAr_0.5895_273.15K",
"material": "Ar",
"file": "Ar/blancett_1970__Z_xAr_0.5895_273.15K.csv",
"table": "tbl_4f20e52886e0",
"quantity": "mixture_compressibility_factor",
"abscissa": "pressure",
"abscissa_unit": "atm",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.5895,
"temperature_k": 273.15
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table I (p. 85; composition label clipped, set by the script): Z = Pv/RT of 41.05 mole percent helium in argon at 273.15 K against the observed pressure, both runs, P <= 150 atm; Z is the fitted virial series at the observed pressure (record notes). x_Ar = 1 - x_He.
blancett_1970/Z_xAr_0.5895_223.15K#
{
"id": "Z_xAr_0.5895_223.15K",
"material": "Ar",
"file": "Ar/blancett_1970__Z_xAr_0.5895_223.15K.csv",
"table": "tbl_4f20e52886e0",
"quantity": "mixture_compressibility_factor",
"abscissa": "pressure",
"abscissa_unit": "atm",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.5895,
"temperature_k": 223.15
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table I (p. 85; composition label clipped, set by the script): Z = Pv/RT of 41.05 mole percent helium in argon at 223.15 K against the observed pressure, both runs, P <= 150 atm; Z is the fitted virial series at the observed pressure (record notes). x_Ar = 1 - x_He.
blancett_1970/Z_xAr_0.7801_323.15K#
{
"id": "Z_xAr_0.7801_323.15K",
"material": "Ar",
"file": "Ar/blancett_1970__Z_xAr_0.7801_323.15K.csv",
"table": "tbl_25b7d6538540",
"quantity": "mixture_compressibility_factor",
"abscissa": "pressure",
"abscissa_unit": "atm",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.7801,
"temperature_k": 323.15
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table I (p. 86): Z = Pv/RT of 21.99 mole percent helium in argon at 323.15 K against the observed pressure, both runs, P <= 150 atm; Z is the fitted virial series at the observed pressure (record notes). x_Ar = 1 - x_He.
blancett_1970/Z_xAr_0.7801_273.15K#
{
"id": "Z_xAr_0.7801_273.15K",
"material": "Ar",
"file": "Ar/blancett_1970__Z_xAr_0.7801_273.15K.csv",
"table": "tbl_25b7d6538540",
"quantity": "mixture_compressibility_factor",
"abscissa": "pressure",
"abscissa_unit": "atm",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.7801,
"temperature_k": 273.15
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table I (p. 86): Z = Pv/RT of 21.99 mole percent helium in argon at 273.15 K against the observed pressure, both runs, P <= 150 atm; Z is the fitted virial series at the observed pressure (record notes). x_Ar = 1 - x_He.
blancett_1970/Z_xAr_0.7801_223.15K#
{
"id": "Z_xAr_0.7801_223.15K",
"material": "Ar",
"file": "Ar/blancett_1970__Z_xAr_0.7801_223.15K.csv",
"table": "tbl_25b7d6538540",
"quantity": "mixture_compressibility_factor",
"abscissa": "pressure",
"abscissa_unit": "atm",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.7801,
"temperature_k": 223.15
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table I (p. 86): Z = Pv/RT of 21.99 mole percent helium in argon at 223.15 K against the observed pressure, both runs, P <= 150 atm; Z is the fitted virial series at the observed pressure (record notes). x_Ar = 1 - x_He.
blancett_1970/B_xAr_0.2000#
{
"id": "B_xAr_0.2000",
"material": "Ar",
"file": "Ar/blancett_1970__B_xAr_0.2000.csv",
"table": "tbl_c09ea288c262",
"quantity": "mixture_second_virial_coefficient",
"unit": "cm3/mol",
"abscissa": "temperature",
"abscissa_unit": "K",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.2
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table II (p. 88): the second virial coefficient B_2 (cc/g mol) of 80.00 mole percent helium in argon at 323.15, 273.15 and 223.15 K, with its standard deviation. x_Ar = 1 - x_He.
blancett_1970/B_xAr_0.4065#
{
"id": "B_xAr_0.4065",
"material": "Ar",
"file": "Ar/blancett_1970__B_xAr_0.4065.csv",
"table": "tbl_c09ea288c262",
"quantity": "mixture_second_virial_coefficient",
"unit": "cm3/mol",
"abscissa": "temperature",
"abscissa_unit": "K",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.4065
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table II (p. 88): the second virial coefficient B_2 (cc/g mol) of 59.35 mole percent helium in argon at 323.15, 273.15 and 223.15 K, with its standard deviation. x_Ar = 1 - x_He.
blancett_1970/B_xAr_0.5895#
{
"id": "B_xAr_0.5895",
"material": "Ar",
"file": "Ar/blancett_1970__B_xAr_0.5895.csv",
"table": "tbl_c09ea288c262",
"quantity": "mixture_second_virial_coefficient",
"unit": "cm3/mol",
"abscissa": "temperature",
"abscissa_unit": "K",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.5895
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table II (p. 88): the second virial coefficient B_2 (cc/g mol) of 41.05 mole percent helium in argon at 323.15, 273.15 and 223.15 K, with its standard deviation. x_Ar = 1 - x_He.
blancett_1970/B_xAr_0.7801#
{
"id": "B_xAr_0.7801",
"material": "Ar",
"file": "Ar/blancett_1970__B_xAr_0.7801.csv",
"table": "tbl_c09ea288c262",
"quantity": "mixture_second_virial_coefficient",
"unit": "cm3/mol",
"abscissa": "temperature",
"abscissa_unit": "K",
"use": "primary",
"parameters": {
"partner": "He",
"mole_fraction": 0.7801
},
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table II (p. 88): the second virial coefficient B_2 (cc/g mol) of 21.99 mole percent helium in argon at 323.15, 273.15 and 223.15 K, with its standard deviation. x_Ar = 1 - x_He.
blancett_1970/B_He#
{
"id": "B_He",
"material": "He",
"file": "He/blancett_1970__B_He.csv",
"table": "tbl_c09ea288c262",
"quantity": "second_virial_coefficient",
"unit": "cm3/mol",
"abscissa": "temperature",
"abscissa_unit": "K",
"use": "primary",
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table II (p. 88): the second virial coefficient B_2 (cc/g mol) of pure helium at 323.15, 273.15 and 223.15 K, with its standard deviation, from the same apparatus; measured ‘only for consistency and for purposes of calculating interaction virial coefficients’ (p. 75).
blancett_1970/B_Ar#
{
"id": "B_Ar",
"material": "Ar",
"file": "Ar/blancett_1970__B_Ar.csv",
"table": "tbl_c09ea288c262",
"quantity": "second_virial_coefficient",
"unit": "cm3/mol",
"abscissa": "temperature",
"abscissa_unit": "K",
"use": "primary",
"uncertainty": {
"column": true,
"level": "1 sigma"
}
}
Table II (p. 88): the second virial coefficient B_2 (cc/g mol) of pure argon at 323.15, 273.15 and 223.15 K, with its standard deviation, from the same apparatus; measured ‘only for consistency and for purposes of calculating interaction virial coefficients’ (p. 75).
Formulas#
No formulas are recorded.
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 review register for the checks and decisions.