<P> This table lists the gas--liquid--solid triple points of several substances . Unless otherwise noted, the data come from the U.S. National Bureau of Standards (now NIST, National Institute of Standards and Technology). </P> <Table> <Tr> <Th> Substance </Th> <Th> T (K) (° C) </Th> <Th> p (kPa) * (atm) </Th> </Tr> <Tr> <Td> Acetylene </Td> <Td> 7002192400000000000 ♠ 192.4 K (− 80.7 ° C) </Td> <Td> 7005120000000000000 ♠ 120 kPa (1.2 atm) </Td> </Tr> <Tr> <Td> Ammonia </Td> <Td> 7002195400000000000 ♠ 195.40 K (− 77.75 ° C) </Td> <Td> 7003606000000000000 ♠ 6.060 kPa (0.05981 atm) </Td> </Tr> <Tr> <Td> Argon </Td> <Td> 7001838100000000000 ♠ 83.81 K (− 189.34 ° C) </Td> <Td> 7004689000000000000 ♠ 68.9 kPa (0.680 atm) </Td> </Tr> <Tr> <Td> Arsenic </Td> <Td> 7003109000000000000 ♠ 1,090 K (820 ° C) </Td> <Td> 7006362800000000000 ♠ 3,628 kPa (35.81 atm) </Td> </Tr> <Tr> <Td> Butane </Td> <Td> 7002134600000000000 ♠ 134.6 K (− 138.6 ° C) </Td> <Td> 6999700000000000000 ♠ 7 × 10 kPa (6.9 × 10 atm) </Td> </Tr> <Tr> <Td> Carbon (graphite) </Td> <Td> 7003476500000000000 ♠ 4,765 K (4,492 ° C) </Td> <Td> 7007101320000000000 ♠ 10,132 kPa (100.00 atm) </Td> </Tr> <Tr> <Td> Carbon dioxide </Td> <Td> 7002216550000000000 ♠ 216.55 K (− 56.60 ° C) </Td> <Td> 7005517000000000000 ♠ 517 kPa (5.10 atm) </Td> </Tr> <Tr> <Td> Carbon monoxide </Td> <Td> 7001681000000000000 ♠ 68.10 K (− 205.05 ° C) </Td> <Td> 7004153700000000000 ♠ 15.37 kPa (0.1517 atm) </Td> </Tr> <Tr> <Td> Chloroform </Td> <Td> 7002175430000000000 ♠ 175.43 K (− 97.72 ° C) </Td> <Td> 7002870000000000000 ♠ 0.870 kPa (0.00859 atm) </Td> </Tr> <Tr> <Td> Deuterium </Td> <Td> 7001186300000000000 ♠ 18.63 K (− 254.52 ° C) </Td> <Td> 7004171000000000000 ♠ 17.1 kPa (0.169 atm) </Td> </Tr> <Tr> <Td> Ethane </Td> <Td> 7001898900000000000 ♠ 89.89 K (− 183.26 ° C) </Td> <Td> 6999800000000000000 ♠ 8 × 10 kPa (7.9 × 10 atm) </Td> </Tr> <Tr> <Td> Ethanol </Td> <Td> 7002150000000000000 ♠ 150 K (− 123 ° C) </Td> <Td> 6996430000000000000 ♠ 4.3 × 10 kPa (4.2 × 10 atm) </Td> </Tr> <Tr> <Td> Ethylene </Td> <Td> 7002104000000000000 ♠ 104.0 K (− 169.2 ° C) </Td> <Td> 7002120000000000000 ♠ 0.12 kPa (0.0012 atm) </Td> </Tr> <Tr> <Td> Formic acid </Td> <Td> 7002281399999999999 ♠ 281.40 K (8.25 ° C) </Td> <Td> 7003220000000000000 ♠ 2.2 kPa (0.022 atm) </Td> </Tr> <Tr> <Td> Helium - 4 (lambda point) </Td> <Td> 7000217680000000000 ♠ 2.1768 K (− 270.9732 ° C) </Td> <Td> 7003504800000000000 ♠ 5.048 kPa (0.04982 atm) </Td> </Tr> <Tr> <Td> Helium - 4 (hcp − bcc − He - II) </Td> <Td> 7000146300000000000 ♠ 1.463 K (− 271.687 ° C) </Td> <Td> 7004260360000000000 ♠ 26.036 kPa (0.25696 atm) </Td> </Tr> <Tr> <Td> Helium - 4 (bcc − He - I − He - II) </Td> <Td> 7000176200000000000 ♠ 1.762 K (− 271.388 ° C) </Td> <Td> 7004297250000000000 ♠ 29.725 kPa (0.29336 atm) </Td> </Tr> <Tr> <Td> Helium - 4 (hcp − bcc − He - I) </Td> <Td> 7000177200000000000 ♠ 1.772 K (− 271.378 ° C) </Td> <Td> 7004300160000000000 ♠ 30.016 kPa (0.29623 atm) </Td> </Tr> <Tr> <Td> Hexafluoroethane </Td> <Td> 7002173080000000000 ♠ 173.08 K (− 100.07 ° C) </Td> <Td> 7004266000000000000 ♠ 26.60 kPa (0.2625 atm) </Td> </Tr> <Tr> <Td> Hydrogen </Td> <Td> 7001138400000000000 ♠ 13.84 K (− 259.31 ° C) </Td> <Td> 7003704000000000000 ♠ 7.04 kPa (0.0695 atm) </Td> </Tr> <Tr> <Td> Hydrogen chloride </Td> <Td> 7002158960000000000 ♠ 158.96 K (− 114.19 ° C) </Td> <Td> 7004139000000000000 ♠ 13.9 kPa (0.137 atm) </Td> </Tr> <Tr> <Td> Iodine </Td> <Td> 7002386650000000000 ♠ 386.65 K (113.50 ° C) </Td> <Td> 7004120700000000000 ♠ 12.07 kPa (0.1191 atm) </Td> </Tr> <Tr> <Td> Isobutane </Td> <Td> 7002113550000000000 ♠ 113.55 K (− 159.60 ° C) </Td> <Td> 6998194809999999999 ♠ 1.9481 × 10 kPa (1.9226 × 10 atm) </Td> </Tr> <Tr> <Td> Krypton </Td> <Td> 7002115760000000000 ♠ 115.76 K (− 157.39 ° C) </Td> <Td> 7004741200000000000 ♠ 74.12 kPa (0.7315 atm) </Td> </Tr> <Tr> <Td> Mercury </Td> <Td> 7002234200000000000 ♠ 234.2 K (− 39.0 ° C) </Td> <Td> 6996165000000000000 ♠ 1.65 × 10 kPa (1.63 × 10 atm) </Td> </Tr> <Tr> <Td> Methane </Td> <Td> 7001906800000000000 ♠ 90.68 K (− 182.47 ° C) </Td> <Td> 7004117000000000000 ♠ 11.7 kPa (0.115 atm) </Td> </Tr> <Tr> <Td> Neon </Td> <Td> 7001245700000000000 ♠ 24.57 K (− 248.58 ° C) </Td> <Td> 7004432000000000000 ♠ 43.2 kPa (0.426 atm) </Td> </Tr> <Tr> <Td> Nitric oxide </Td> <Td> 7002109500000000000 ♠ 109.50 K (− 163.65 ° C) </Td> <Td> 7004219200000000000 ♠ 21.92 kPa (0.2163 atm) </Td> </Tr> <Tr> <Td> Nitrogen </Td> <Td> 7001631800000000000 ♠ 63.18 K (− 209.97 ° C) </Td> <Td> 7004126000000000000 ♠ 12.6 kPa (0.124 atm) </Td> </Tr> <Tr> <Td> Nitrous oxide </Td> <Td> 7002182340000000000 ♠ 182.34 K (− 90.81 ° C) </Td> <Td> 7004878500000000000 ♠ 87.85 kPa (0.8670 atm) </Td> </Tr> <Tr> <Td> Oxygen </Td> <Td> 7001543600000000000 ♠ 54.36 K (− 218.79 ° C) </Td> <Td> 7002152000000000000 ♠ 0.152 kPa (0.00150 atm) </Td> </Tr> <Tr> <Td> Palladium </Td> <Td> 7003182500000000000 ♠ 1,825 K (1,552 ° C) </Td> <Td> 7000350000000000000 ♠ 3.5 × 10 kPa (3.5 × 10 atm) </Td> </Tr> <Tr> <Td> Platinum </Td> <Td> 7003204500000000000 ♠ 2,045 K (1,772 ° C) </Td> <Td> 6999200000000000000 ♠ 2 × 10 kPa (2.0 × 10 atm) </Td> </Tr> <Tr> <Td> Radon </Td> <Td> 7002202000000000000 ♠ 202 K (− 71 ° C) </Td> <Td> 7004700000000000000 ♠ 70 kPa (0.69 atm) </Td> </Tr> <Tr> <Td> (mono) Silane </Td> <Td> 7001884800000000000 ♠ 88.48 K (− 184.67 ° C) </Td> <Td> 7001196439999999999 ♠ 0.019644 kPa (0.00019387 atm) </Td> </Tr> <Tr> <Td> Sulfur dioxide </Td> <Td> 7002197690000000000 ♠ 197.69 K (− 75.46 ° C) </Td> <Td> 7003167000000000000 ♠ 1.67 kPa (0.0165 atm) </Td> </Tr> <Tr> <Td> Titanium </Td> <Td> 7003194100000000000 ♠ 1,941 K (1,668 ° C) </Td> <Td> 7000530000000000000 ♠ 5.3 × 10 kPa (5.2 × 10 atm) </Td> </Tr> <Tr> <Td> Uranium hexafluoride </Td> <Td> 7002337170000000000 ♠ 337.17 K (64.02 ° C) </Td> <Td> 7005151700000000000 ♠ 151.7 kPa (1.497 atm) </Td> </Tr> <Tr> <Td> Water </Td> <Td> 7002273160000000000 ♠ 273.16 K (0.01 ° C) </Td> <Td> 7002611657000000000 ♠ 0.611657 kPa (0.00603659 atm) </Td> </Tr> <Tr> <Td> Xenon </Td> <Td> 7002161300000000000 ♠ 161.3 K (− 111.8 ° C) </Td> <Td> 7004815000000000000 ♠ 81.5 kPa (0.804 atm) </Td> </Tr> <Tr> <Td> Zinc </Td> <Td> 7002692650000000000 ♠ 692.65 K (419.50 ° C) </Td> <Td> 7001650000000000000 ♠ 0.065 kPa (0.00064 atm) </Td> </Tr> </Table> <Tr> <Th> Substance </Th> <Th> T (K) (° C) </Th> <Th> p (kPa) * (atm) </Th> </Tr> <Tr> <Td> Acetylene </Td> <Td> 7002192400000000000 ♠ 192.4 K (− 80.7 ° C) </Td> <Td> 7005120000000000000 ♠ 120 kPa (1.2 atm) </Td> </Tr>

What is triple point of water and why is it called triple point