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Tris

Athanor · official

C4H11NO3 · 121.14 g/mol

IUPAC name: 2-amino-2-(hydroxymethyl)propane-1,3-diol

Also called tris buffer, THAM, tromethamine, tris(hydroxymethyl)aminomethane

Reagents
Open in Athanor
The structure of Tris
Drawn from its SMILES with RDKit
Harmful or irritantWarningCauses skin irritation · Causes serious eye irritation · May cause respiratory irritation

Names and identifiers

IUPAC name
2-amino-2-(hydroxymethyl)propane-1,3-diol
Synonyms
tris buffer, THAM, tromethamine
+ 40 more

tris(hydroxymethyl)aminomethane, Trometamol, TROMETHAMINE, Tris(Hydroxymethyl)aminomethane, Tham, Trisamine, 2-Amino-2-(hydroxymethyl)-1,3-propanediol, Tris buffer, Tromethane, Tris-base, Trisaminol, Pehanorm, Talatrol, Tutofusin tris, Tris-steril, Addex-tham, 1,3-Propanediol, 2-amino-2-(hydroxymethyl)-, Trispuffer, Trimethylolaminomethane, Tris Amino, Tris, free base, Aminotrimethylolmethane, Aminotris(hydroxymethyl)methane, Tris(hydroxymethyl)methylamine, THAM-E, Tris (buffering agent), Tromethamolum, Trometamolum, 2-Amino-2-methylol-1,3-propanediol, DTXSID2023723, NSC-6365, Methanamine, 1,1,1-tris(hydroxymethyl)-, Tris-hydroxymethyl-aminomethan, 023C2WHX2V, Tris(hydroxymethyly)amino methane, NSC6365, DTXCID503723, NSC65434, Tri(hydroxymethyl)aminomethane, Tris-Mg(II)-KCl Buffer

Molecular formula
C4H11NO3
Empirical formula
C4H11NO3
Molecular weight
121.14 g/mol
Exact mass
121.07389
CAS number
77-86-1
PubChem CID
6503
Canonical SMILES
C(C(CO)(CO)N)O
Isomeric SMILES
C(C(CO)(CO)N)O
InChI
InChI=1S/C4H11NO3/c5-4(1-6,2-7)3-8/h6-8H,1-3,5H2
InChIKey
LENZDBCJOHFCAS-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

Appearance
Liquid; Large Crystals; Dry Powder; Other Solid[1]
2 values

From EPA Chemical Data Reporting (CDR), the most authoritative source here.

ValueAs writtenSource
–shownLiquid; Large Crystals; Dry Powder; Other Solid[1] EPA Chemical Data Reporting (CDR)
–WHITE, CRYSTALLINE POWDER[2] Hazardous Substances Data Bank (HSDB)cites Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 773
Odor
SLIGHT, CHARACTERISTIC ODOR[2]
pKa
pKa = 8.07[2]

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms
8
Rings
0
Aromatic rings
0
Fraction sp³ carbons (Fsp3)
1
H-bond donors
4
H-bond acceptors
4
Rotatable bonds
3
TPSA (Ų)
86.7
Formal charge
0
XLogP3
-2.9 PubChem
Complexity
54 PubChem
Stereocenters
None
Double-bond geometry
None specified
Point group
C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

  • C39.66%
  • H9.15%
  • N11.56%
  • O39.62%

Isotope pattern

100%121.0744.9%122.077123.078

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P
-2.34 Crippen (Wildman and Crippen 1999)
log S (water solubility)
1.08 ESOL (Delaney 2004), log mol/L
Synthetic accessibility
3.16 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

  • Molecular weight ≤ 500: 121.14
  • log P ≤ 5 (Crippen): -2.34
  • H-bond donors ≤ 5: 4
  • H-bond acceptors ≤ 10: 4

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Warning

Most widely reported: 1,192 company reports to ECHA. Source [3].

  • Harmful or irritant
  • H315Causes skin irritation (80.2% of reports)
  • H319Causes serious eye irritation (80.3% of reports)
  • H335May cause respiratory irritation (70.8% of reports)

Precautionary statements: P261, P264, P264+P265, P271, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P337+P317, P362+P364, P403+P233, P405, P501

View all classifications (2)
  • [3] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 19.7% (235 of 1192) of reports.
  • [3] European Chemicals Agency (ECHA) · 1,192 reports · WarningH315, H319, H335

Storage

  • Tromethamine injection should be stored at 20-25 °C; freezing should be avoided. Unused portions of tromethamine solution should be discarded.[2]

Safety data sheets on the supplier’s page: Sigma-Aldrich, abcr GmbH, MedChemexpress MCE.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

  1. [1]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
  2. [2]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
  3. [3]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
  4. [4]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
  5. [5]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
  6. [6]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
  7. [7]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
  8. [8]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
  9. [9]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
  10. ·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
  11. ·Literature on PubChem

Data last updated 2026-10-14.