| class="wikitable"
!name
!formula
!ratio
urea:
solute
!crystal system
!space group
!unit cell
!volume
!density
!comment
!reference |
| hydrogen peroxide; urea (1:1)
|HOOH•CH4N2O
|1:1
|orthorhombic
|Pnca
|a 6.732 b 4.8207 c 12.873 Z=4
|
|
|decomposes slowly at room temperature
|[{{Cite journal |last1=Fritchie |first1=C. J. |last2=McMullan |first2=R. K. |date=1981-05-01 |title=Neutron diffraction study of the 1:1 urea:hydrogen peroxide complex at 81 K |url=https://scripts.iucr.org/cgi-bin/paper?S0567740881005116 |journal=Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry |volume=37 |issue=5 |pages=1086–1091 |doi=10.1107/S0567740881005116 |bibcode=1981AcCrB..37.1086F |issn=0567-7408|url-access=subscription }}] |
| urea; acetic acid (1:2)
|2CH3COOH•CH4N2O
|1:2
|monoclinic
|P21/n
|a 7.6549 b 10.1351 c 11.5219 β 99.570° Z=4
|881.47
|1.358
|unstable in air
|[{{Cite journal |last1=Cruz-Cabeza |first1=Aurora J. |last2=Day |first2=Graeme M. |last3=Jones |first3=William |date=2008-10-10 |title=Towards Prediction of Stoichiometry in Crystalline Multicomponent Complexes |url=https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.200800668 |journal=Chemistry – A European Journal |language=en |volume=14 |issue=29 |pages=8830–8836 |doi=10.1002/chem.200800668 |pmid=18752227 |issn=0947-6539|url-access=subscription }}] |
| oxalic acid; urea (1:1)
|C2H2O4•CH4N2O
|1:1
|monoclinic
|C2/c
|a 13.0625 b 6.6437 c 6.8478 β 92.474°
|
|
|
|[{{Cite journal |last1=Harkema |first1=S. |last2=Ter Brake |first2=J. H. M. |date=1979-04-15 |title=Structure and thermal expansion of urea–oxalic acid (1:1) |url=https://scripts.iucr.org/cgi-bin/paper?S0567740879005446 |journal=Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry |volume=35 |issue=4 |pages=1011–1013 |doi=10.1107/S0567740879005446|bibcode=1979AcCrB..35.1011H |url-access=subscription }}] |
| oxalic acid; urea (1:2)
|C2H2O4•2CH4N2O
|2:1
|monoclinic
|P2/c
|a 5.058 b 12.400 c 6.964 β 98.13°
|
|
|
|[{{Cite journal |last1=Harkema |first1=S. |last2=Bats |first2=J. W. |last3=Weyenberg |first3=A. M. |last4=Feil |first4=D. |date=1972-05-15 |title=The crystal structure of urea oxalic acid (2:1) |url=https://scripts.iucr.org/cgi-bin/paper?S0567740872004789 |journal=Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry |volume=28 |issue=5 |pages=1646–1648 |doi=10.1107/S0567740872004789|bibcode=1972AcCrB..28.1646H }}] |
| Urea - N,N-dimethylformamide (3:1)
|3CH4N2O·C3H7NO
|3:1
|triclinic
|P{{overbar|1}}
|a = 7.525 b = 9.866 c = 10.821 α = 65.61° β = 79.43° γ = 70.76° Z=2
|689.7
|1.219
|colourless @150K
|[{{Cite journal |last1=Fernandes |first1=Philippe |last2=Florence |first2=Alastair J. |last3=Fabbiani |first3=Francesca |last4=David |first4=William I. F. |last5=Shankland |first5=Kenneth |date=2007-12-15 |title=Urea– N,N -dimethylformamide (3/1) |url=https://scripts.iucr.org/cgi-bin/paper?S1600536807059934 |journal=Acta Crystallographica Section E: Structure Reports Online |volume=63 |issue=12 |pages=o4861 |doi=10.1107/S1600536807059934 |bibcode=2007AcCrE..63o4861F |issn=1600-5368|url-access=subscription }}] |
| N,N-dimethylacetamide; urea (1:1)
|C4H9NO·CH4N2O
|1:1
|monoclinic
|C2/c
|a = 7.2770 b = 17.5394 c = 7.3789 β = 119.450° Z=4
|820.11
|1.192
|colourless @120K
|[{{Cite journal |last1=Fernandes |first1=Philippe |last2=Florence |first2=Alastair J. |last3=Fabbiani |first3=Francesca |last4=David |first4=William I. F. |last5=Shankland |first5=Kenneth |date=2008-02-15 |title=Urea– N,N -dimethylacetamide (1/1) |url=https://scripts.iucr.org/cgi-bin/paper?S1600536807067232 |journal=Acta Crystallographica Section E: Structure Reports Online |volume=64 |issue=2 |pages=o355 |doi=10.1107/S1600536807067232 |issn=1600-5368 |pmc=2960435 |pmid=21201387|bibcode=2008AcCrE..64O.355F }}] |
| Urea malonic acid
|
|1:1
|monoclinic
|P2/c
|a 13.091 b 5.455 c 9.933 β 104.39°
|
|
|
|[{{Cite journal |last=G.Bandoli, D.A.Clemente, M.Brustolon, C.Corvaja, C.Pinzino, A.Colligiani |date=1980 |title= X-ray diffraction and ENDOR investigation of hydrogen bonding in malonic acid-urea 1 : 1 adduct|journal=Molecular Physics |volume=39 |issue=5 |pages=1145–1152|doi=10.1080/00268978000100951 |bibcode=1980MolPh..39.1145B }}] |
| Maleic acid; urea (1:1)
|
|1:1
|monoclinic
|Cc
|a 5.144 b 9.999 c 14.80 β 95.1°
|
|
|
|[{{Cite journal |last=Videnova-Adrabińska |first=Veneta |date=January 1996 |title=The hydrogen bond as a design element in crystal engineering. Two- and three-dimensional building blocks of crystal architecture |url=https://linkinghub.elsevier.com/retrieve/pii/0022286095089756 |journal=Journal of Molecular Structure |language=en |volume=374 |issue=1–3 |pages=199–222 |doi=10.1016/0022-2860(95)08975-6|bibcode=1996JMoSt.374..199V |url-access=subscription }}] |
| Succinic acid bis urea
|
|2:1
|monoclinic
|P21/c
|a 5.637 b 8.243 c 12.262 β 96.75° Z=2
|565.81
|1.41
|
|[{{Cite journal |last1=Wiedenfeld |first1=H. |last2=Knoch |first2=F. |date=1990-06-15 |title=Harnstoffkomplexe mit Dicarbonsäuren. 1. Mitteilung: die Struktur von Bernsteinsäure–Harnstoff |url=https://scripts.iucr.org/cgi-bin/paper?S0108270189010024 |journal=Acta Crystallographica Section C Crystal Structure Communications |volume=46 |issue=6 |pages=1038–1040 |doi=10.1107/S0108270189010024|bibcode=1990AcCrC..46.1038W |url-access=subscription }}] |
| Maleic acid; urea (2:1)
|
|2:1
|monoclinic
|P21/n
|a 5.661 b 11.754 c 19.173 β 91.56°
|
|
|
| |
| Fumaric acid; urea (1:2)
|
|1:2
|monoclinic
|P21/c
|a 5.540 b 8.227 c 12.426 β 97.22°
|
|
|
|[{{Cite journal |last=Videnova-Adrabińska |first=V. |date=1996-12-01 |title=Symmetry constraints, molecular recognition and crystal engineering. Comparative structural studies of urea–butanedioic and urea– E -butanedioic acid (2:1) cocrystals |url=https://scripts.iucr.org/cgi-bin/paper?S0108768196005216 |journal=Acta Crystallographica Section B Structural Science |volume=52 |issue=6 |pages=1048–1056 |doi=10.1107/S0108768196005216 |bibcode=1996AcCrB..52.1048V |issn=0108-7681|url-access=subscription }}] |
| D-Tartaric
|
|1:1
|orthorhombic
|P212121
|a 17.229 b 9.824 c 5.056 Z=4
|
|1.63
|transparent 255 to 1370 nm; SHG 3×KDP
|[{{Cite journal |date=28 July 1996 |title=Growth and characterization of urea-(D) tartaric acid single crystal |journal=Chinese Science Bulletin |volume=41 |issue=16 |pages=1392–1395 |doi=10.1360/sb1996-41-16-1392|doi-broken-date=1 November 2024 }}] |
| DL-Tartaric
|
|1:1
|monoclinic
|P21
|a 7.6973 b 23.3310 c 4.8727 β 100.82°
|
|
|NLO; transparent from 240 to 1950 nm
|[{{Cite journal |last1=Lü |first1=M. K. |last2=Meng |first2=F. Q. |last3=Yang |first3=Z. H. |last4=Yu |first4=W. T. |last5=Zeng |first5=H. |date=1996 |title=Growth and Characterization of Urea-(DL) Tartaric Acid Single Crystals |url=https://onlinelibrary.wiley.com/doi/10.1002/crat.2170310702 |journal=Crystal Research and Technology |language=en |volume=31 |issue=7 |pages=833–836 |doi=10.1002/crat.2170310702|bibcode=1996CryRT..31..833L |url-access=subscription }}] |
| Gluatric acid bis urea
|
|2:1
|monoclinic
|C2/c
|a 11.954 b 10.932 c 9.078 β 97.86° Z=4
|
|
|
|[{{Cite journal |last1=Videnova-Adrabińska |first1=Veneta |last2=Etter |first2=Margaret C. |date=December 1995 |title=Urea-glutaric acid (2:1) structural aggregates as building blocks for crystal engineering |url=http://link.springer.com/10.1007/BF01671077 |journal=Journal of Chemical Crystallography |language=en |volume=25 |issue=12 |pages=823–829 |doi=10.1007/BF01671077 |bibcode=1995JCCry..25..823V |s2cid=94295605 |issn=1074-1542|url-access=subscription }}] |
| Itaconic acid
|
|1:1
|monoclinic
|P21/c
|a 12.71 b 5.2695 c 13.833β 104.78°
|
|
|
|[{{Cite journal |last1=Smith |first1=Graham |last2=Kennard |first2=Colin H. L. |last3=Byriel |first3=Karl A. |date=1997 |title=The Preparation and Crystal Structures of a Series of Urea Adducts: with Fumaric Acid (2 : 1), with Itaconic Acid (1 : 1) and with Cyanuric Acid (1 : 1) |url=http://www.publish.csiro.au/?paper=C97123 |journal=Australian Journal of Chemistry |language=en |volume=50 |issue=10 |pages=1021 |doi=10.1071/C97123 |issn=0004-9425|url-access=subscription }}] |
| 2-bromotetradecane urea
|
|
|hexagonal
|P6122
|a=8.2582 c=10.9937
|
|
|298K
|[{{Cite journal |last1=Yeo |first1=Lily |last2=Harris |first2=Kenneth DM |date=1999-12-05 |title=Temperature-dependent structural properties of a solid urea inclusion compound containing chiral guest molecules: 2-bromotetradecane/urea |url=https://cdnsciencepub.com/doi/10.1139/v99-215 |journal=Canadian Journal of Chemistry |language=en |volume=77 |issue=12 |pages=2105–2118 |doi=10.1139/v99-215 |issn=0008-4042|url-access=subscription }}] |
| 2-bromotetradecane urea
|
|
|orthorhombic
|C2221
|
|
|
|207K
| |
| 2-bromotetradecane urea
|
|
|monoclinic
|P21
|a 16.338(1)Å b 10.9665(8)Å c 16.338(1)Å, α 90° β 60.00°
|
|
|
| |
| 4-amino benzoic acid; urea (2:1)
|(C7H7NO2)2(CH4N2O)
|1:2
|orthorhombic
|Pnab
|a=7.4159 b=11.870 c=18.750
|
|
|
|[{{Cite journal |last1=Smith |first1=Graham |last2=Baldry |first2=Katherine E. |last3=Byriel |first3=Karl A. |last4=Kennard |first4=Colin H. L. |date=1997 |title=Molecular Cocrystals of Carboxylic Acids. XXV The Utility of Urea in Structure Making with Carboxylic Acids and the Crystal Structures of a Set of Six Adducts with Aromatic Acids |url=http://www.publish.csiro.au/?paper=C96199 |journal=Australian Journal of Chemistry |language=en |volume=50 |issue=7 |pages=727 |doi=10.1071/C96199 |issn=0004-9425|url-access=subscription }}] |
| salicylic acid; urea (1:1)
|
|1:1
|monoclinic
|C2/c
|a=22.206 b=5.108 c=17.177 β=106.18 Z=8°
|
|1.407
|
|[{{Cite journal |last1=Hsu |first1=I-Nan |last2=Gellert |first2=Robert W. |date=February 1983 |title=The 1:1 crystal complex of salicylic acid and urea |url=http://link.springer.com/10.1007/BF01666795 |journal=Journal of Crystallographic and Spectroscopic Research |language=en |volume=13 |issue=1 |pages=43–48 |doi=10.1007/BF01666795 |bibcode=1983JCCry..13...43H |s2cid=96740153 |issn=0277-8068|url-access=subscription }}] |
| 5-nitro salicylic acid; urea (2:1)
|(C7H5NO5)2(CH4N2O)
|1:2
|triclinic
|P{{overbar|1}}
|a=6.9889 b=12.1968 c=12.3622 α=60.923° β=81.169° γ=76.938°
|
|
|
| |
| 3,5-dinitro salicylic acid; urea (1:1)
|(C7H4N2O7)(CH4N2O)
|1:1
|monoclinic
|P21/c
|a=4.942 b=22.337 c=10.389 β=100.92°
|
|
|
| |
| o-phthalic acid; urea (1:1)
|
|1:1
|triclinic
|P{{overbar|1}}
|a=7.422 b=7.662 c=10.088 α=85.95° β=82.01° γ=65.14°
|
|
|
| |
| urea : 1,4-dioxane (1 : 1)
|C4H8O2•C3H6O
|1:1
|monoclinic
|P2/c
|a=6.7949 b=4.5234 c=12.2711 β=95.701° Z=2
|
|
|
| |
| urea : morpholine (1 : 1)
|C4H8ON•C3H6O
|1:1
|orthorhombic
|Pbcm
|a=4.5847 b=19.131 c=8.9047 Z=4
|
|
|
| |
| 3,5-dimethylpyridine bis(urea)
|(CH3)2C5H3N•2C3H6O
|2:1
|orthorhombic
|Abm2
|a=21.737 b=7.2102 c=15.590 Z=8
|2443.4
|1.236
|at 173K
|[{{Cite journal |last1=Taouss |first1=Christina |last2=Jones |first2=Peter G. |date=2014-05-06 |title=Lutidine adducts of urea: molecular mechanisms for twinning effects on cooling |url=http://xlink.rsc.org/?DOI=C4CE00560K |journal=CrystEngComm |language=en |volume=16 |issue=25 |pages=5695–5704 |doi=10.1039/C4CE00560K |s2cid=97000988 |issn=1466-8033|doi-access=free }}] |
| 3,5-dimethylpyridine bis(urea)
|(CH3)2C5H3N•2C3H6O
|2:1
|monoclinic
|Cc
|a=8.5829 b=21.4843 c=7.2050 β=114.405° Z=4
|1209.87
|1.248
|at 100K
| |
| 2,6-dimethylpyridine urea
|(CH3)2C5H3N•C3H6O
|1:1
|triclinic
|P{{overbar|1}}
|a=7.4126 b=7.6720 c=8.1731 α=88.391° β=83.564° γ=80.059° Z=2
|454.92
|1.221
|at 100K
| |
| urea 2,6-dimethylpyridine
|(CH3)2C5H3N•C3H6O
|1:1
|monoclinic
|C2/c
|a=1.426 b=11.1168 c=7.4318 β=101.23° Z=4
|925.9
|1.200
|at 200K
| |
| 2,6-dimethylpyridine bis(urea)
|(CH3)2C5H3N•2C3H6O
|2:1
|orthorhombic
|Pnma
|a=8.0772 b=7.2986 c=20.4169 Z=4
|1203.64
|1.254
|at 100K
| |
| 2,6-dimethylpyridine bis(urea)
|(CH3)2C5H3N•2C3H6O
|2:1
|monoclinic
|C2/c
|a=11.160 b=11.5421 c=10.910 β=116.12°
|
|
|
| |
| 2-picoline; urea (1:1)
|C6H7N·CH4N2O
|1:1
|orthorhombic
|Pbca
|a = 7.471 b = 14.916 c = 15.338 Z = 8
|1709.2
|
|
|[{{Cite journal |last1=Ashurov |first1=Jamshid |last2=Ibragimov |first2=Bakhtiyar |last3=Talipov |first3=Samat |date=2012-02-15 |title=2-Methylpyridine–urea (1/1) |url=https://scripts.iucr.org/cgi-bin/paper?S1600536812002164 |journal=Acta Crystallographica Section E: Structure Reports Online |volume=68 |issue=2 |pages=o504 |doi=10.1107/S1600536812002164 |issn=1600-5368 |pmc=3275249 |pmid=22347105|bibcode=2012AcCrE..68O.504A }}] |
| Urea pyrazine-2,3-dicarboxylic acid
|
|1:1
|monoclinic
|P21/n
|a=7.725 b=10.2530 c=12.612 β=97.997°
|
|
|
| |
| bipyridine urea
|
|
|triclinic
|P{{overbar|1}}
|a=7.200 b=8.297 c=9.835 α=75.849° β=70.744° γ =73.045°
|
|
|
|[{{Cite journal |last1=Donnelly |first1=Paul S. |last2=Skelton |first2=Brian W. |last3=White |first3=Allan H. |date=2003 |title='Neutralmolekülcomplexe'—Structural Characterization of Some Adducts of Urea and Thiourea with N,{{prime|N}}-Bidentate Aromatic Bases |url=http://www.publish.csiro.au/?paper=CH03015 |journal=Australian Journal of Chemistry |language=en |volume=56 |issue=12 |pages=1249 |doi=10.1071/CH03015 |issn=0004-9425|url-access=subscription }}] |
| bipyridine urea
|
|
|triclinic
|P{{overbar|1}}
|a=7.2862 b=8.3747 c=9.8647 α=76.061° β=72.789° γ=74.121°
|
|
|
| |
| 1,10-Phenanthroline urea
|
|1:1
|monoclinic
|C2/c
|a=14.342 b=12.002 c=7.3724 β 116.743°
|
|
|
| |
| 2,9-Dimethyl-1,10-phenanthroline urea
|
|1:1
|orthorhombic
|Cmcm
|a=11.370 b=17.351 c=7.3593
|
|
|
| |
| sodium chloride; urea; water (1:1:1)
|NaCl·CH4N2O·H2O
|1:1
|triclinic
|
|a = 6.44 Å, b = 5.245Å, c = 17.312 Å, and a=90°, β=90.15°, γ=90°
|588.76
|
|SHG 1.53 × KDP, birefringence 0.084@1064 nm UV edge 209 nm
|[{{Cite journal |last1=Huang |first1=Tingting |last2=Wang |first2=Ying |last3=Yang |first3=Daqing |last4=Zhang |first4=Bingbing |date=2023-08-21 |title=NaCl·CH 4 N 2 O·H 2 O: An Organic–Inorganic Hybrid Ultraviolet Nonlinear Optical Crystal with Optimized Comprehensive Properties |url=https://pubs.acs.org/doi/10.1021/acs.inorgchem.3c02025 |journal=Inorganic Chemistry |language=en |volume=62 |issue=33 |pages=13626–13631 |doi=10.1021/acs.inorgchem.3c02025 |pmid=37556794 |s2cid=260773568 |issn=0020-1669|url-access=subscription }}][{{Cite journal |last=Ilango |first=E. |date=August 2014 |title=Optical and Dielectric Characterization of a new Non linear Optical Urea Sodium Chloride single crystal by slow evaporation technique |url=https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=7f4b4e661529760125e9b25452c0261c51dc37dc |journal=International Journal of ChemTech Research |volume=6 |issue=6 |pages=3237–3240}}] |
| Bis(2-3-isopropyl-7-oxocyclohepta-1,3,5-trien-1-olato)bis[(3-isopropyl-7-oxocyclohepta-1,3,5-trien-1-olato)copper(II)]-urea-acetone (1/6/2)
|[Cu2(C10H11O2)4]·6CH4N2O·2C3H6O
|5:1
|monoclinic
|P21/c
|a 17.0125 b 11.0470 c 17.2731 β 110.385° Z=2
|3042.95
|1.371
|green
|[{{Cite journal |last=Ho |first=Douglas M. |date=2010-10-15 |title=A urea adduct of bis(hinokitiolato)copper(II) |url=https://scripts.iucr.org/cgi-bin/paper?S0108270110035602 |journal=Acta Crystallographica Section C Crystal Structure Communications |volume=66 |issue=10 |pages=m294–m299 |doi=10.1107/S0108270110035602 |pmid=20921607 |bibcode=2010AcCrC..66M.294H |issn=0108-2701|url-access=subscription }}] |
| aqua(N-salicylidene-rac-alaninato- O,N,O')copper(II)-urea (1/1)
|
|1:1
|triclinic
|P{{overbar|1}}
|a = 7.637, b = 8.509 c = 10.716 α = 93.10° β = 97.97° γ= 106.37° Z= 2,
|658.5
|
|blue
|[{{Cite journal |last=Warda |first=S. A. |date=1999-03-01 |title=Crystal structure of dimeric aqua(N-salicylidene-rac-alaninato- O,N,O')copper(II)-urea (1/1), C11H15CuN3O5 |journal=Zeitschrift für Kristallographie - New Crystal Structures |volume=214 |issue=1 |pages=77–78 |doi=10.1515/ncrs-1999-0141 |s2cid=96765755 |issn=2197-4578|doi-access=free }}] |
| Aqua[9-(1,8-diazafluoren-9-ylidene)amino-1,8-diazafluorenato]hydroxo(urea)zinc(II) urea solvate
|[Zn(C22H12N5)(OH)(CH4N2O)(H2O)]•C4N2O
|1:1
|monoclinic
|P21/c
|a 7.8637 b 16.0133 c 17.9513 β 101.358° Z=4
|2216.2
|1.687
|purple
|[{{Cite journal |last1=Komen |first1=R. P. |last2=Miskelly |first2=G. M. |last3=Oliver |first3=A. |last4=Rickard |first4=C. E. F. |date=1999-08-15 |title=Aqua[9-(1,8-diazafluoren-9-ylidene)amino-1,8-diazafluorenato]hydroxo(urea)zinc(II) urea solvate |url=https://scripts.iucr.org/cgi-bin/paper?S0108270199005995 |journal=Acta Crystallographica Section C Crystal Structure Communications |volume=55 |issue=8 |pages=1213–1215 |doi=10.1107/S0108270199005995 |bibcode=1999AcCrC..55.1213K |issn=0108-2701|url-access=subscription }}] |
| Pentakis(carbamide)dioxoneptunium(V) nitrate
|[NpO2{OC(NH2)2}5](NO3)
|
|monoclinic
|P21
|a = 11.142, b = 7.6379 c = 11.143 β = 108.9° Z = 2
|897.1
|
|
|[{{Cite journal |last1=Budantseva |first1=N. A. |last2=Andreev |first2=G. B. |last3=Krot |first3=N. N. |last4=Antipin |first4=M. Yu. |date=2003 |title=[No title found] |url=http://link.springer.com/10.1023/A:1022892000172 |journal=Russian Journal of Coordination Chemistry |volume=29 |issue=3 |pages=222–226 |doi=10.1023/A:1022892000172|s2cid=91233429 |url-access=subscription }}] |
| Bis[(isothiocyanato)tetraureadioxoneptunium(V)] urea
|{NpO2(NCS)[OC(NH2)2]4}2 · OC(NH2)2
|
|tetragonal
|P43212
|a=7.851 c=56.84 Z=4
|3504
|2.265
|light green
|[{{Cite journal |last=Andreev |first=G. B. |date=2000 |title=[No title found] |url=http://link.springer.com/10.1023/A:1026699418221 |journal=Doklady Chemistry |volume=375 |issue=4/6 |pages=285–288 |doi=10.1023/A:1026699418221|s2cid=92340176 |url-access=subscription }}] |