Table 3.

Experimental speed of sound data for the R-125/1234yf mixtures

$x_1\mathbf{/mole\; frac}$	$x_2\mathbf{/mole\; frac}$	$u_{\text{c}}\left(x_1\right)\mathbf{/mole\; frac}$	T/K	p/MPa	w/m∙s−1	$U_{\text{c}}(w)$/%
0.33351	0.66649	0.00067	229.997	0.107	716.21	0.044
0.33351	0.66649	0.00067	235.006	0.744	697.54	0.045
0.33351	0.66649	0.00067	240.002	0.803	675.15	0.047
0.33351	0.66649	0.00067	245.002	0.818	652.50	0.049
0.33351	0.66649	0.00067	250.004	0.825	629.84	0.052
0.33351	0.66649	0.00067	254.994	0.836	607.26	0.055
0.33351	0.66649	0.00067	259.986	0.849	584.75	0.059
0.33351	0.66649	0.00067	269.992	4.667	575.51	0.058
0.33351	0.66649	0.00067	274.995	7.870	582.88	0.055
0.33351	0.66649	0.00067	279.999	11.062	590.02	0.053
0.33351	0.66649	0.00067	269.990	4.084	570.31	0.059
0.33351	0.66649	0.00067	274.995	7.259	577.72	0.057
0.33351	0.66649	0.00067	279.999	10.444	585.08	0.054
0.33351	0.66649	0.00067	284.999	13.619	592.26	0.052
0.33351	0.66649	0.00067	269.989	1.474	545.69	0.066
0.33351	0.66649	0.00067	274.993	4.529	553.43	0.062
0.33351	0.66649	0.00067	279.998	7.594	561.08	0.059
0.33351	0.66649	0.00067	285.000	10.710	568.96	0.056
0.33351	0.66649	0.00067	290.001	13.780	576.34	0.053
0.33351	0.66649	0.00067	274.992	1.591	524.38	0.071
0.33351	0.66649	0.00067	279.998	4.500	532.30	0.067
0.33351	0.66649	0.00067	284.999	7.424	540.15	0.063
0.33351	0.66649	0.00067	290.002	10.348	547.79	0.060
0.33351	0.66649	0.00067	294.996	13.264	555.22	0.057
0.33351	0.66649	0.00067	279.996	1.536	501.19	0.078
0.33351	0.66649	0.00067	284.998	4.294	509.34	0.073
0.33351	0.66649	0.00067	290.000	7.065	517.35	0.068
0.33351	0.66649	0.00067	294.997	9.839	525.16	0.064
0.33351	0.66649	0.00067	284.998	1.500	477.98	0.086
0.33351	0.66649	0.00067	290.001	4.115	486.39	0.080
0.33351	0.66649	0.00067	294.997	6.738	494.59	0.074
0.33351	0.66649	0.00067	299.998	9.369	502.59	0.070
0.33351	0.66649	0.00067	290.000	1.462	454.43	0.096
0.33351	0.66649	0.00067	294.996	3.941	463.24	0.088
0.33351	0.66649	0.00067	299.998	6.425	471.71	0.082
0.33351	0.66649	0.00067	304.997	8.914	479.88	0.076
0.33351	0.66649	0.00067	294.994	1.527	431.92	0.107
0.33351	0.66649	0.00067	299.996	3.868	440.96	0.098
0.33351	0.66649	0.00067	304.997	6.217	449.66	0.090
0.33351	0.66649	0.00067	309.999	8.573	458.02	0.083
0.33351	0.66649	0.00067	299.995	1.727	411.00	0.119
0.33351	0.66649	0.00067	304.996	3.942	420.33	0.108
0.33351	0.66649	0.00067	310.000	6.167	429.22	0.099
0.33351	0.66649	0.00067	314.993	8.391	437.71	0.091
0.33351	0.66649	0.00067	304.993	1.803	388.15	0.136
0.33351	0.66649	0.00067	309.997	3.882	397.71	0.122
0.33351	0.66649	0.00067	314.994	5.967	406.78	0.111
0.33351	0.66649	0.00067	320.004	8.057	415.38	0.102
0.33351	0.66649	0.00067	309.997	2.071	367.74	0.153
0.33351	0.66649	0.00067	314.991	4.030	378.01	0.137
0.33351	0.66649	0.00067	320.004	6.003	387.27	0.124
0.33351	0.66649	0.00067	325.009	7.977	396.01	0.113
0.33351	0.66649	0.00067	314.991	2.342	348.44	0.173
0.33351	0.66649	0.00067	320.002	4.183	357.97	0.154
0.33351	0.66649	0.00067	325.007	6.033	367.70	0.138
0.33351	0.66649	0.00067	330.000	7.883	376.48	0.125
0.33351	0.66649	0.00067	320.001	2.505	326.33	0.202
0.33351	0.66649	0.00067	325.008	4.201	336.07	0.178
0.33351	0.66649	0.00067	330.000	5.910	345.16	0.159
0.33351	0.66649	0.00067	330.000	5.932	346.00	0.158
0.33351	0.66649	0.00067	335.004	7.640	354.50	0.142
0.33351	0.66649	0.00067	325.006	2.664	303.74	0.240
0.33351	0.66649	0.00067	325.006	2.663	303.60	0.240
0.33351	0.66649	0.00067	329.998	4.248	314.22	0.208
0.33351	0.66649	0.00067	335.004	5.836	323.61	0.184
0.33351	0.66649	0.00067	329.997	2.987	284.75	0.279
0.33351	0.66649	0.00067	335.003	4.461	295.33	0.239
0.33351	0.66649	0.00067	340.008	5.942	304.74	0.209
0.33351	0.66649	0.00067	345.012	7.446	314.03	0.184
0.66643	0.33357	0.00034	229.999	0.471	687.99	0.046
0.66643	0.33357	0.00034	235.010	1.062	668.75	0.047
0.66643	0.33357	0.00034	240.003	1.077	645.73	0.049
0.66643	0.33357	0.00034	245.002	1.089	622.55	0.052
0.66643	0.33357	0.00034	250.004	1.120	599.62	0.055
0.66643	0.33357	0.00034	254.994	3.686	598.44	0.054
0.66643	0.33357	0.00034	259.986	7.231	605.38	0.052
0.66643	0.33357	0.00034	265.002	10.792	612.28	0.049
0.66643	0.33357	0.00034	269.992	14.364	619.27	0.048
0.66643	0.33357	0.00034	274.995	17.942	626.20	0.046
0.66643	0.33357	0.00034	279.999	21.515	633.02	0.044
0.66643	0.33357	0.00034	254.991	3.664	598.25	0.054
0.66643	0.33357	0.00034	254.991	1.737	582.05	0.058
0.66643	0.33357	0.00034	259.985	5.206	589.26	0.055
0.66643	0.33357	0.00034	269.991	12.115	603.11	0.050
0.66643	0.33357	0.00034	259.984	1.506	557.12	0.062
0.66643	0.33357	0.00034	259.984	1.440	556.52	0.063
0.66643	0.33357	0.00034	269.990	7.924	570.42	0.056
0.66643	0.33357	0.00034	274.995	11.247	577.89	0.053
0.66643	0.33357	0.00034	269.991	4.788	543.12	0.063
0.66643	0.33357	0.00034	274.995	7.953	550.80	0.059
0.66643	0.33357	0.00034	279.999	11.132	558.41	0.056
0.66643	0.33357	0.00034	269.990	1.601	511.98	0.073
0.66643	0.33357	0.00034	274.994	4.576	519.80	0.068
0.66643	0.33357	0.00034	279.999	7.586	527.73	0.064
0.66643	0.33357	0.00034	285.001	10.594	535.45	0.060
0.66643	0.33357	0.00034	274.993	1.601	488.69	0.080
0.66643	0.33357	0.00034	279.998	4.428	496.85	0.075
0.66643	0.33357	0.00034	285.001	7.269	504.89	0.069
0.66643	0.33357	0.00034	290.002	10.119	512.75	0.065
0.66643	0.33357	0.00034	279.997	1.521	464.28	0.089
0.66643	0.33357	0.00034	284.999	4.185	472.69	0.082
0.66643	0.33357	0.00034	290.002	6.863	480.91	0.076
0.66643	0.33357	0.00034	294.998	9.551	488.94	0.071
0.66643	0.33357	0.00034	284.998	1.626	441.78	0.099
0.66643	0.33357	0.00034	290.001	4.149	450.52	0.091
0.66643	0.33357	0.00034	294.997	6.686	459.01	0.084
0.66643	0.33357	0.00034	299.998	9.233	467.24	0.078
0.66643	0.33357	0.00034	290.000	1.510	416.01	0.114
0.66643	0.33357	0.00034	294.995	3.867	425.01	0.103
0.66643	0.33357	0.00034	299.999	6.240	433.69	0.095
0.66643	0.33357	0.00034	304.996	8.625	442.10	0.087
0.66643	0.33357	0.00034	294.995	1.476	390.66	0.131
0.66643	0.33357	0.00034	299.997	3.687	400.09	0.118
0.66643	0.33357	0.00034	304.995	5.916	409.15	0.107
0.66643	0.33357	0.00034	309.999	8.157	417.85	0.098
0.66643	0.33357	0.00034	299.997	1.466	364.80	0.154
0.66643	0.33357	0.00034	304.996	3.547	374.94	0.137
0.66643	0.33357	0.00034	309.999	5.634	384.42	0.123
0.66643	0.33357	0.00034	314.993	7.728	393.41	0.112
0.66643	0.33357	0.00034	320.003	9.825	401.91	0.102
0.66643	0.33357	0.00034	304.993	1.937	347.12	0.171
0.66643	0.33357	0.00034	309.997	3.889	357.22	0.152
0.66643	0.33357	0.00034	314.989	5.848	366.71	0.136
0.66643	0.33357	0.00034	320.003	7.793	375.31	0.123
0.66643	0.33357	0.00034	325.008	9.761	383.72	0.112
0.66643	0.33357	0.00034	309.995	1.979	321.21	0.207
0.66643	0.33357	0.00034	314.992	3.779	331.71	0.180
0.66643	0.33357	0.00034	320.003	5.598	341.52	0.160
0.66643	0.33357	0.00034	325.007	7.421	350.69	0.143
0.66643	0.33357	0.00034	314.991	2.245	299.27	0.245
0.66643	0.33357	0.00034	320.003	3.919	310.10	0.211
0.66643	0.33357	0.00034	325.008	5.605	319.71	0.184
0.66643	0.33357	0.00034	330.001	7.308	329.48	0.163

Compositions listed ($x_1$, $x_2$) and composition standard uncertainty $\left(u_{\text{c}}\left(x_1\right)\right)$ are mole fractions. The standard uncertainties for temperature $\left(T\right)$ and pressure $\left(p\right)$ are $u_{\text{c}}\left(T\right)$= 0.004 and $u_{\text{c}}\left(p\right)$ = 0.014 MPa, respectively. Speed of sound values listed $\left(w\right)$ is averaged from up to twelve measurements at each state point. Relative combined expanded speed of sound uncertainties, $U_{\text{c}}\left(w\right)$, are determined with a coverage factor k = 2 and include effects of composition, temperature, pressure, time delay between echo arrivals, and path length calibration as described in detail elsewhere [3, 4, 14]. Lines in the table separate the pseudoisochores