Phase Changes

Triple point temperature (Ttri) and pressure (Ptri), critical temperature (Tcri) and pressure (Pcri),
and phase transition temperature (Ttran) for species observed on Titan.
Species
Ttri (K)
Ptri (bar)
Tcri (K)
Pcri (bar)
Ttran (K)
Phase
Transition Note
CH4
90.686±0.010
0.117±0.001
190.564±0.010
45.992±0.073
20.509±0.047
crystal II-crystal I
C2H6
90.3560±0.0050
(1.1 ± 0.1) × 10-5
305.322±0.035
48.72±0.23
89.816±0.027
89.726±0.050
crystal II-crystal I
crystal III-crystal II
C2H4
103.966±0.016
(1.2 ± 0.1) × 10−3
282.350±0.025
50.417±0.068
n/a
n/a
C2H2
191.66±0.94
1.2±0.1
308.39±0.35
62.06±0.67
133.0±1.0
crystal II-crystal I
C4H2
237.7±2.5
0.13 ± 0.01
410±16
26.0±10.0
n/a
n/a
C6H6
278.6877±0.0023
(4.7 ± 0.1) × 10−2
562.02±0.13
49.06±0.20
n/a
n/a
C3H8
85.400±0.054
(1.8 ± 0.2) × 10−9
369.89±0.14
42.51±0.21
80.40±0.10
metastable crystal-crystal I
C3H6
87.850±0.020
(8 ± 1) × 10−9
364.21±0.26
45.55±0.76
n/a
n/a
C3H4-a
136.70±0.53
1.8 ± 0.1) × 10−4
393.9±4.0
62.80±4.40
n/a
n/a
C3H4-p
169.87±0.77
∼ 3.8 × 10−3
402.7±1.5
56.58±0.81
n/a
n/a
HCN
259.871±0.091
0.1865 ± 0.0015
456.65±0.50
49.70±3.90
170.40±0.50
crystal II-crystal I
HC3N
280±1
∼ 0.25
527±11
52.00±27.00
n/a
n/a
CO2
216.5890±0.0077
5.18 ± 0.01
304.128±0.038
73.77±0.20
n/a
n/a
CH3CN
229.349±0.053
∼ 1.9 × 10−3
545.41±0.40
48.66±0.27
216.9±0.1
crystal II-crystal I
C2H5CN
180.4±1.2
∼ 1.7 × 10−6
561.26±0.20
42.60±0.89
176.964±0.005
crystal II-crystal I
C2H3CN
189.642±0.050
(3.5 ± 0.5) × 10−5
540.0±2.0
46.50±2.80
162.50±0.10
crystal II-crystal I
C2N2
245.29±0.10
0.77 ± 0.03
397.1±3.0
62.50±4.00
n/a
n/a
C4N2
293.0±1.3
1.7 x 10-1
496±22
66.00±55.00
n/a
n/a