Editing Carbon dioxide (section)

=== Physical properties ===
{{further|Carbon dioxide data}}
[[File:Dry Ice Pellets Subliming.jpg|right|thumb|Pellets of "dry ice", a common form of solid carbon dioxide]]
Carbon dioxide is colorless. At low concentrations, the gas is odorless; however, at sufficiently high concentrations, it has a sharp, acidic odor.<ref name=AirProductsMSDS>{{cite web |title=Carbon Dioxide |website=Air Products |url=http://www.airproducts.com/~/media/Files/PDF/company/product-summary-carbon-dioxide.pdf?la=en |access-date=28 April 2017 |archive-date=29 July 2020 |archive-url=https://web.archive.org/web/20200729131131/http://www.airproducts.com/~/media/Files/PDF/company/product-summary-carbon-dioxide.pdf?la=en |url-status=dead}}</ref> At [[standard temperature and pressure]], the density of carbon dioxide is around 1.98&nbsp;kg/m<sup>3</sup>, about 1.53 times that of [[Earth's atmosphere|air]].<ref>{{cite web |url=https://www.engineeringtoolbox.com/gas-density-d_158.html |title=Gases – Densities |publisher=Engineering Toolbox |access-date=21 November 2020 |archive-date=2 March 2006 |archive-url=https://web.archive.org/web/20060302054722/https://www.engineeringtoolbox.com/gas-density-d_158.html |url-status=live}}</ref>

Carbon dioxide has no liquid state at pressures below 0.51795(10) [[MPa]]<ref name = "Span_1999" /> (5.11177(99) [[Standard atmosphere (unit)|atm]]). At a pressure of 1&nbsp;atm (0.101325 MPa), the gas [[deposition (physics)|deposits]] directly to a solid at temperatures below 194.6855(30) K<ref name = "Span_1999" /> (−78.4645(30) °C) and the solid [[sublimation (chemistry)|sublimes]] directly to a gas above this temperature. In its solid state, carbon dioxide is commonly called [[dry ice]].

[[File:Carbon dioxide pressure-temperature phase diagram.svg|right|thumb|upright=1.15|Pressure–temperature [[phase diagram]] of carbon dioxide. Note that it is a log-lin chart.]]

[[Liquid carbon dioxide]] forms only at [[pressure]]s above 0.51795(10) MPa<ref name = "Span_1999" /> (5.11177(99) atm); the [[triple point]] of carbon dioxide is 216.592(3) K<ref name = "Span_1999" /> (−56.558(3) °C) at 0.51795(10) MPa<ref name = "Span_1999" /> (5.11177(99) atm) (see phase diagram). The [[Critical point (thermodynamics)|critical point]] is 304.128(15) K<ref name = "Span_1999" /> (30.978(15) °C) at 7.3773(30) MPa<ref name = "Span_1999" /> (72.808(30) atm). Another form of solid carbon dioxide observed at high pressure is an [[amorphous]] glass-like solid.<ref>{{cite journal | vauthors = Santoro M, Gorelli FA, Bini R, Ruocco G, Scandolo S, Crichton WA | title = Amorphous silica-like carbon dioxide | journal = Nature | volume = 441 | issue = 7095 | pages = 857–860 | date = June 2006 | pmid = 16778885 | doi = 10.1038/nature04879 | s2cid = 4363092 | bibcode = 2006Natur.441..857S}}</ref> This form of glass, called ''[[amorphous carbonia|carbonia]]'', is produced by [[supercooling]] heated {{CO2}} at extreme pressures (40–48&nbsp;[[GPa]], or about 400,000 atmospheres) in a [[diamond anvil]]. This discovery confirmed the theory that carbon dioxide could exist in a glass state similar to other members of its elemental family, like [[silicon dioxide]] (silica glass) and [[germanium dioxide]]. Unlike silica and germania glasses, however, carbonia glass is not stable at normal pressures and reverts to gas when pressure is released.

At temperatures and pressures above the critical point, carbon dioxide behaves as a [[supercritical fluid]] known as [[supercritical carbon dioxide]].

{{clear}}

Table of thermal and physical properties of saturated liquid carbon dioxide:<ref name=Holman>{{Cite book |last=Holman |first=Jack P. |title=Heat Transfer |publisher=McGraw-Hill Companies, Inc. |year=2002 |isbn=9780072406559 |edition=9th |location=New York, NY |pages=600–606 |language=English}}</ref><ref name=Incropera>{{Cite book |last1=Incropera |last2=Dewitt |last3=Bergman |last4=Lavigne |first1=Frank P. |first2=David P. |first3=Theodore L. |first4=Adrienne S. |title=Fundamentals of Heat and Mass Transfer |publisher=John Wiley and Sons, Inc. |year=2007 |isbn=9780471457282 |edition=6th |location=Hoboken, NJ |pages=941–950 |language=English}}</ref>
{|class="wikitable mw-collapsible mw-collapsed" style="text-align:right;"
![[Temperature]]<br>(°C)
![[Density]]<br>(kg/m<sup>3</sup>)
![[Specific heat]]<br>(kJ/(kg⋅K))
![[Kinematic viscosity]]<br>(m<sup>2</sup>/s)
![[Thermal conductivity]]<br>(W/(m⋅K))
![[Thermal diffusivity]]<br>(m<sup>2</sup>/s)
![[Prandtl Number]]
|-
|−50
|1156.34
|1.84
|1.19 × 10<sup>−7</sup>
|0.0855
|4.02 × 10<sup>−8</sup>
|2.96
|-
|-
|−40
|1117.77
|1.88
|1.18 × 10<sup>−7</sup>
|0.1011
|4.81 × 10<sup>−8</sup>
|2.46
|-
|-
|−30
|1076.76
|1.97
|1.17 × 10<sup>−7</sup>
|0.1116
|5.27 × 10<sup>−8</sup>
|2.22
|-
|-
|−20
|1032.39
|2.05
|1.15 × 10<sup>−7</sup>
|0.1151
|5.45 × 10<sup>−8</sup>
|2.12
|-
|-
|−10
|983.38
|2.18
|1.13 × 10<sup>−7</sup>
|0.1099
|5.13 × 10<sup>−8</sup>
|2.2
|-
|-
|0
|926.99
|2.47
|1.08 × 10<sup>−7</sup>
|0.1045
|4.58 × 10<sup>−8</sup>
|2.38
|-
|-
|10
|860.03
|3.14
|1.01 × 10<sup>−7</sup>
|0.0971
|3.61 × 10<sup>−8</sup>
|2.8
|-
|-
|20
|772.57
|5
|9.10 × 10<sup>−8</sup>
|0.0872
|2.22 × 10<sup>−8</sup>
|4.1
|-
|30
|597.81
|36.4
|8.00 × 10<sup>−8</sup>
|0.0703
|0.279 × 10<sup>−8</sup>
|28.7
|-
|}
Table of thermal and physical properties of carbon dioxide ({{CO2}}) at atmospheric pressure:<ref name=Holman/><ref name=Incropera/>
{|class="wikitable mw-collapsible mw-collapsed" style="text-align:right;"
!Temperature<br>(K)
!Density<br>(kg/m<sup>3</sup>)
!Specific heat<br>(kJ/(kg⋅°C))
![[Dynamic viscosity]]<br>(kg/(m⋅s))
!Kinematic viscosity<br>(m<sup>2</sup>/s)
!Thermal conductivity<br>(W/(m⋅°C))
!Thermal diffusivity<br>(m<sup>2</sup>/s)
!Prandtl Number
|-
|220
|2.4733
|0.783
|1.11 × 10<sup>−5</sup>
|4.49 × 10<sup>−6</sup>
|0.010805
|5.92 × 10<sup>−6</sup>
|0.818
|-
|250
|2.1657
|0.804
|1.26 × 10<sup>−5</sup>
|5.81 × 10<sup>−6</sup>
|0.012884
|7.40 × 10<sup>−6</sup>
|0.793
|-
|300
|1.7973
|0.871
|1.50 × 10<sup>−5</sup>
|8.32 × 10<sup>−6</sup>
|0.016572
|1.06 × 10<sup>−5</sup>
|0.77
|-
|350
|1.5362
|0.9
|1.72 × 10<sup>−5</sup>
|1.12 × 10<sup>−5</sup>
|0.02047
|1.48 × 10<sup>−5</sup>
|0.755
|-
|400
|1.3424
|0.942
|1.93 × 10<sup>−5</sup>
|1.44 × 10<sup>−5</sup>
|0.02461
|1.95 × 10<sup>−5</sup>
|0.738
|-
|450
|1.1918
|0.98
|2.13 × 10<sup>−5</sup>
|1.79 × 10<sup>−5</sup>
|0.02897
|2.48 × 10<sup>−5</sup>
|0.721
|-
|500
|1.0732
|1.013
|2.33 × 10<sup>−5</sup>
|2.17 × 10<sup>−5</sup>
|0.03352
|3.08 × 10<sup>−5</sup>
|0.702
|-
|550
|0.9739
|1.047
|2.51 × 10<sup>−5</sup>
|2.57 × 10<sup>−5</sup>
|0.03821
|3.75 × 10<sup>−5</sup>
|0.685
|-
|600
|0.8938
|1.076
|2.68 × 10<sup>−5</sup>
|3.00 × 10<sup>−5</sup>
|0.04311
|4.48 × 10<sup>−5</sup>
|0.668
|-
|650
|0.8143
|1.1
|2.88 × 10<sup>−5</sup>
|3.54 × 10<sup>−5</sup>
|0.0445
|4.97 × 10<sup>−5</sup>
|0.712
|-
|700
|0.7564
|1.13
|3.05 × 10<sup>−5</sup>
|4.03 × 10<sup>−5</sup>
|0.0481
|5.63 × 10<sup>−5</sup>
|0.717
|-
|750
|0.7057
|1.15
|3.21 × 10<sup>−5</sup>
|4.55 × 10<sup>−5</sup>
|0.0517
|6.37 × 10<sup>−5</sup>
|0.714
|-
|800
|0.6614
|1.17
|3.37 × 10<sup>−5</sup>
|5.10 × 10<sup>−5</sup>
|0.0551
|7.12 × 10<sup>−5</sup>
|0.716
|}