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Drybench Calc.
Common reagents: formula weights and hydrates
A table of 75 bench reagents with formulas, hydrate forms, PubChem identifiers and formula weights computed from the IUPAC 2021 atomic weights.
75 reagents, each with its PubChem identifiers; pick one to open the bench sheet with its formula weight.
| Reagent | Formula | FW (g/mol) | Category | pKa (25 °C) | PubChem CID |
|---|---|---|---|---|---|
| Tris base | C4H11NO3 | 121.14 | Buffers | 8.07 | 6503 |
| Tris hydrochloride | C4H12ClNO3 | 157.59 | Buffers | 8.07 | 93573 |
| HEPES | C8H18N2O4S | 238.30 | Buffers | 7.56 | 23831 |
| HEPES sodium salt | C8H17N2NaO4S | 260.28 | Buffers | 7.56 | 2724248 |
| MOPS | C7H15NO4S | 209.26 | Buffers | 7.18 | 70807 |
| MES | C6H13NO4S | 195.23 | Buffers | 6.27 | 78165 |
| MES monohydrate1 H₂O | C6H13NO4S·1H2O | 213.25 | Buffers | 6.27 | 16218417 |
| PIPES | C8H18N2O6S2 | 302.36 | Buffers | 7.14 | 79723 |
| Bicine | C6H13NO4 | 163.17 | Buffers | 8.33 | 8761 |
| Tricine | C6H13NO5 | 179.17 | Buffers | 8.13 | 79784 |
| CHES | C8H17NO3S | 207.29 | Buffers | 9.39 | 66898 |
| TAPS | C7H17NO6S | 243.27 | Buffers | 8.44 | 121591 |
| TES | C6H15NO6S | 229.25 | Buffers | 7.55 | 81831 |
| CAPS | C9H19NO3S | 221.32 | Buffers | 10.50 | 70815 |
| Imidazole | C3H4N2 | 68.08 | Buffers | 6.99 | 795 |
| Glycine | C2H5NO2 | 75.07 | Buffers | 9.78 | 750 |
| Sodium acetate | C2H3NaO2 | 82.03 | Buffers | 4.76 | 31372 |
| Sodium acetate trihydrate3 H₂O | C2H3NaO2·3H2O | 136.08 | Buffers | 4.76 | 23665404 |
| Acetic acid | C2H4O2 | 60.05 | Buffers | 4.76 | 176 |
| Citric acid | C6H8O7 | 192.12 | Buffers | 3.13, 4.76, 6.40 | 311 |
| Citric acid monohydrate1 H₂O | C6H8O7·1H2O | 210.14 | Buffers | 3.13, 4.76, 6.40 | 22230 |
| Sodium citrate dihydrate2 H₂O | C6H5Na3O7·2H2O | 294.10 | Buffers | 3.13, 4.76, 6.40 | 71474 |
| Sodium phosphate monobasic monohydrate1 H₂O | H2NaO4P·1H2O | 137.99 | Buffers | 7.20 | 516949 |
| Sodium phosphate dibasic | HNa2O4P | 141.96 | Buffers | 7.20 | 24203 |
| Sodium phosphate dibasic heptahydrate7 H₂O | HNa2O4P·7H2O | 268.06 | Buffers | 7.20 | 6096963 |
| Potassium phosphate monobasic | H2KO4P | 136.08 | Buffers | 7.20 | 516951 |
| Potassium phosphate dibasic | HK2O4P | 174.17 | Buffers | 7.20 | 24450 |
| Sodium bicarbonate | CHNaO3 | 84.01 | Buffers | 6.35, 10.33 | 516892 |
| Sodium carbonate | CNa2O3 | 105.99 | Buffers | 10.33 | 10340 |
| Boric acid | BH3O3 | 61.83 | Buffers | 9.24 | 7628 |
| Ammonium acetate | C2H7NO2 | 77.08 | Buffers | 4.76, 9.24 | 517165 |
| Ammonium chloride | ClH4N | 53.49 | Salts | 9.24 | 25517 |
| Ammonium sulfate | H8N2O4S | 132.13 | Salts | 9.24 | 6097028 |
| Sodium chloride | ClNa | 58.44 | Salts | 5234 | |
| Potassium chloride | ClK | 74.55 | Salts | 4873 | |
| Calcium chloride | CaCl2 | 110.98 | Salts | 5284359 | |
| Calcium chloride dihydrate2 H₂O | CaCl2·2H2O | 147.01 | Salts | 6093260 | |
| Magnesium chloride hexahydrate6 H₂O | Cl2Mg·6H2O | 203.30 | Salts | 24644 | |
| Magnesium sulfate | MgO4S | 120.36 | Salts | 24083 | |
| Magnesium sulfate heptahydrate7 H₂O | MgO4S·7H2O | 246.47 | Salts | 24843 | |
| Zinc chloride | Cl2Zn | 136.28 | Salts | 5727 | |
| Zinc sulfate heptahydrate7 H₂O | O4SZn·7H2O | 287.54 | Salts | 62640 | |
| Copper(II) sulfate pentahydrate5 H₂O | CuO4S·5H2O | 249.68 | Salts | 24463 | |
| Iron(III) chloride hexahydrate6 H₂O | Cl3Fe·6H2O | 270.29 | Salts | 6093258 | |
| Manganese(II) chloride tetrahydrate4 H₂O | Cl2Mn·4H2O | 197.90 | Salts | 643989 | |
| Lithium chloride | ClLi | 42.39 | Salts | 433294 | |
| Caesium chloride | ClCs | 168.36 | Salts | 24293 | |
| Sodium azide | N3Na | 65.01 | Preservatives | 33557 | |
| Sodium hydroxide | HNaO | 40.00 | Bases | 14798 | |
| Potassium hydroxide | HKO | 56.11 | Bases | 14797 | |
| EDTA | C10H16N2O8 | 292.24 | Chelators | 6049 | |
| EDTA disodium salt dihydrate2 H₂O | C10H14N2Na2O8·2H2O | 372.24 | Chelators | 636371 | |
| EGTA | C14H24N2O10 | 380.35 | Chelators | 6207 | |
| DTT | C4H10O2S2 | 154.24 | Reductants | 439196 | |
| TCEP hydrochloride | C9H16ClO6P | 286.65 | Reductants | 2734570 | |
| 2-Mercaptoethanol | C2H6OS | 78.13 | Reductants | 1567 | |
| Glycerol | C3H8O3 | 92.09 | Cryoprotectants | 753 | |
| D-Glucose | C6H12O6 | 180.16 | Sugars and polyols | 5793 | |
| D-Glucose monohydrate1 H₂O | C6H12O6·1H2O | 198.17 | Sugars and polyols | 22814120 | |
| Sucrose | C12H22O11 | 342.30 | Sugars and polyols | 5988 | |
| D-Trehalose dihydrate2 H₂O | C12H22O11·2H2O | 378.33 | Sugars and polyols | 181978 | |
| D-Mannitol | C6H14O6 | 182.17 | Sugars and polyols | 6251 | |
| Urea | CH4N2O | 60.06 | Denaturants | 1176 | |
| Guanidine hydrochloride | CH6ClN3 | 95.53 | Denaturants | 5742 | |
| SDS | C12H25NaO4S | 288.38 | Detergents | 3423265 | |
| CHAPS | C32H58N2O7S | 614.88 | Detergents | 107670 | |
| PMSF | C7H7FO2S | 174.19 | Inhibitors | 4784 | |
| IPTG | C9H18O5S | 238.30 | Inducers | 656894 | |
| Ampicillin sodium | C16H18N3NaO4S | 371.39 | Antibiotics | 23663979 | |
| Kanamycin sulfate | C18H38N4O15S | 582.58 | Antibiotics | 441374 | |
| Chloramphenicol | C11H12Cl2N2O5 | 323.13 | Antibiotics | 5959 | |
| DMSO | C2H6OS | 78.13 | Solvents | 679 | |
| ATP disodium salt | C10H14N5Na2O13P3 | 551.15 | Nucleotides | 13803 | |
| NAD+ | C21H27N7O14P2 | 663.43 | Cofactors | 5892 | |
| Spermidine | C7H19N3 | 145.25 | Other | 1102 |
PubChem (NCBI): CIDs, InChIKeys and formulas read 2026-10-06. Goldberg RN, Kishore N, Lennen RM. J Phys Chem Ref Data 2002;31:231-370. IUPAC CIAAW 2021 standard atomic weights.
Worked example
- Formula weights are exact sums of the CIAAW 2021 standard atomic weights; hydrates add 18.015 g/mol per water.
- PubChem's CID and InChIKey identify each reagent; no CAS numbers are used.
Method
- Formula weight from the molecular formula. Prohaska T et al. Standard atomic weights of the elements 2021 (IUPAC Technical Report). Pure Appl Chem 2022;94:573-600. doi:10.1515/pac-2019-0603; ciaaw.org, read 6 October 2026.Checked against a CIAAW 2021 sum in Python's decimal module, with the formula from RDKit 2026.03.6, exactly on 58 fixtures (6 October 2026).
Constants
- ciaaw-2021: IUPAC CIAAW 2021 standard atomic weights, conventional values for interval elements
Limits
- For research and education only, and not medical advice: the stock, dilution and buffer calculations here are not for dosing or clinical preparation.
- Formula weights use the IUPAC 2021 conventional atomic weights, so a vendor label may differ in the third decimal; a weight typed from the vial or a certificate of analysis overrides every computed value.
- The reagent table holds 75 common reagents as single compounds; mixtures such as kanamycin lots, polymers such as Triton X-100 and proteins such as albumin have no single formula weight and are not in it.