Section: 5 | pH Scale for Aqueous Solutions |
Help Manual

Page of 1
Type a page number and hit Enter.
  Back to Search Results
Type a page number and hit Enter.
Additional Information
Summary of table differences
No records found.
How to Cite this Reference
The recommended form of citation is:
John R. Rumble, ed., CRC Handbook of Chemistry and Physics, 103rd Edition (Internet Version 2022), CRC Press/Taylor & Francis, Boca Raton, FL.
If a specific table is cited, use the format: "Physical Constants of Organic Compounds," in CRC Handbook of Chemistry and Physics, 103rd Edition (Internet Version 2022), John R. Rumble, ed., CRC Press/Taylor & Francis, Boca Raton, FL.


A. K. Covington

A Working Party of IUPAC, after extensive considerations over five years, has produced a report (1) which sets pH firmly within the International System of Units (SI). A summary of these important developments is given below.

The concept of pH is unique among the commonly encountered physicochemical quantities in that, in terms of its definition,

pH = − lg aH     (1)

it involves a single ion quantity, the activity of the hydrogen ion, which is immeasurable by any thermodynamically valid method and requires a convention for its evaluation.

pH was originally defined by Sørensen (Ref. 2) in terms of the concentration of hydrogen ions (in modern nomenclature) as pH = − lg (cH/co) where cH is the hydrogen ion concentration in mol dm–3, and co = 1 mol dm–3 is the standard amount concentration. Subsequently (Ref. 3), it was accepted as more satisfactory to define pH in terms of the relative activity of hydrogen ions in solution

pH = − lg aH = − lg (mHγH/mo)      (2)

where aH is the relative (molality basis) activity and γH is the molal activity coefficient of the hydrogen ion H+ at the molality mH, and mo the standard molality. The quantity pH is intended to be a measure of the activity of hydrogen ions in solution. However, since it is defined in terms of a quantity that cannot be measured by a thermodynamically valid method, eqn. (2) can only be considered a notional definition of pH.

pH being a single ion quantity, it is not determinable in terms of a fundamental (or base) unit of any measurement system, and there is difficulty providing a proper basis for the traceability of pH measurements. A satisfactory approach is now available in that pH determinations can be incorporated into the International System (SI) if they can be traced to measurements made using a method that fulfils the definition of a ‘primary method of measurement’ (Ref. 4).

The essential feature of a primary method is that it must operate according to a well-defined measurement equation in which all of the variables can be determined experimentally in terms of SI units. Any limitation in the determination of the experimental variables, or in the theory, must be included within the estimated uncertainty of the method if traceability to the SI is to be established. If a convention were used without an estimate of its uncertainty, true traceability to SI would not be established. The electrochemical cell without liquid junction, known as the Harned cell (Ref. 5), fulfills the definition of a primary method for the measurement of the acidity function, p(aHγCl), and subsequently of the pH of buffer solutions.

The Harned cell is written as

Pt | H2 | buffer S, Cl | AgCl | Ag (Cell I)

and contains a standard buffer, S, with chloride ions, as potassium or sodium chloride, added in order to use the silver–silver chloride electrode as reference electrode. The application of the Nernst equation to the spontaneous cell reaction of Cell I:

½ H2 + AgCl → Ag(s) + H+ + Cl

yields the potential difference EI of the cell (corrected to 1 atm [101.325 kPa], the partial pressure of hydrogen gas used in electrochemistry in preference to 100 kPa) as

EI = Eo − (RT/F)In 10 lg [(mHγH/mo)(mClγCl/mo)]       (3)

which can be rearranged, since aH = mHγH/mo, to give the acidity function

p(aHγCl) = − lg(aHγCl) = (EIEo)/[(RT/F)In 10] + lg(mCl/mo)      (4)

where Eo is the standard potential difference of the cell, and hence of the silver–silver chloride electrode, and γCl is the activity coefficient of the chloride ion.

The standard potential difference of the silver–silver chloride electrode, Eo, is determined from a Harned cell in which only HCl is present at a fixed molality (e.g., m = 0.01 mol kg–1)

Pt | H2 | HCl (m) | AgCl | Ag (Cell Ia)

The application of the Nernst equation to the HCl cell (Ia) gives

Ela = Eo – (2RT/F)In 10 lg[(mHCl/mo)(γ±HCl)]      (5)

where EIa has been corrected to 1 atmosphere partial pressure of hydrogen gas (101.325 kPa) and γ±HCl is the mean ionic activity coefficient of HCl.

Values of the activity coefficient (γ±HCl) at molality 0.01 mol kg–1 and various temperatures were given by Bates and Robinson (Ref. 6). The standard potential difference depends on the method of preparation of the electrodes, but individual determinations of the activity coefficient of HCl at 0.01 mol kg–1 are more uniform than values of Eo. Hence the practical determination of the potential difference of the cell with HCl at 0.01 mol kg–1 is recommended at 298.15 K at which the mean ionic activity coefficient is 0.904. (It is unnecessary to repeat the measurement of Eo at other temperatures but simply to correct published smoothed values by the observed difference in Eo at 298.15 K.)

In national metrology institutes (NMIs), measurements of Cells I and Ia are often done simultaneously in a thermostat bath. Subtracting eqn. (5) from eqn. (3) gives

ΔE = ElEla = – (RT/F)In 10{lg[(mHγH/mo)(mClγCl/mo)] – lg[(mHCl/mo)2γ2±HCl]}

which is independent of the standard potential difference. Therefore, the subsequently calculated pH does not depend on the standard potential difference and hence does not depend on the assumption that the standard potential of the hydrogen electrode is zero at all temperatures. Therefore, the Harned cell gives an exact comparison between hydrogen ion activities at different temperatures.

The quantity p(aHγCl) = − lg (aHγCl), on the left-hand side of (4), is called the acidity function (5). To obtain the quantity pH according to eqn. (2) from the acidity function, it is necessary to evaluate lg γCl independently. This is done in two steps: (i) the value of lg (aHγCl) at zero chloride molality, lg (aHγCl)o, is evaluated and (ii) a value for the activity of the chloride ion γoCl , at zero chloride molality (sometimes referred to as the limiting or ‘trace’ activity coefficient) is calculated using the Bates-Guggenheim convention (Ref. 7). The value of lg (aHγCl)o corresponding to zero chloride molality is determined by linear extrapolation of measurements using Harned cells with at least three added molalities of sodium or potassium chloride (I < 0.1 mol kg–1).

The value of lg (aH γCl)o corresponding to zero chloride molality is determined by linear extrapolation of measurements using Harned cells with at least three added molalities of sodium or potassium chloride (I < 0.1 mol kg–1) in accord with eqn. (7):

− lg (aHγCl) = − lg (aHγCl)o + SmCl        (7)

where S is an empirical, temperature dependent, constant.

The Bates-Guggenheim convention (Ref. 7) assumes that the trace activity coefficient of the chloride ion γoCl is given by

lg γoCl = − A I1/2/(1 + Ba I1/2)         (8)

where A is the Debye-Hückel temperature dependent constant (limiting slope), a is the mean distance of closest approach of the ions (ion size parameter), Ba is set equal to 1.5 (mol kg–1)–1/2 at all temperatures in the range 5–50 °C, and I is the ionic strength of the buffer (which for its evaluation requires knowledge of appropriate acid dissociation constants).

The various stages in the assignment of primary standard pH values are combined in eqn. (9), which is derived from eqns. (4), (5), and (8)

pH(PS) = lim mCl→o {(EIEo)/[(RT/F)In 10] + lg (mCl/mo)} − A I1/2/[1 + 1.5 (I/mo)1/2]          (9)

In order for a particular buffer solution to be considered a primary buffer solution, it must be of the “highest metrological” quality (Ref. 4) in accordance with the definition of a primary standard. It is recommended that it have the following attributes (Ref. 9):

  1. High buffer value in the range 0.016–0.07 (mol OH)/pH.
  2. Small dilution value at half concentration (change in pH with change in buffer concentration) in the range 0.01–0.20.
  3. Small dependence of pH on temperature less than ±0.01 K–1.
  4. Low residual liquid junction potential <0.01 in pH.
  5. Ionic strength ≤0.1 mol kg–1 to permit applicability of Bates-Guggenheim convention.
  6. NMI certificate for specific batch.
  7. Reproducible purity of preparation (lot to lot differences of |ΔpH(PS)| < 0.003).
  8. Long-term stability of stored solid material.

Values for the above and other important parameters for the primary and secondary buffer materials are given in Table 1. Column definitions for Table 1 are as follows.

Column heading Definition
Name Name of salt or solid substance
Formula Molecular formula of solid or substance
Molality Molality of standard buffer solution, in mol kg-1
Molar mass Molar mass of salt or solid substance, in g mol-1
Density Density of standard buffer solution, in g mL-1
Amount conc. at 20 °C Concentration amount at 20 °C, in mol dm-3
Mass in g to make 1 dm3 Mass of salt or solid substance needed to make 1 dm3 = molar mass × Amount conc. at 20 °C; in g
Dilution value ΔpH1/2 Change of pH value at half concentration, in pH units
Buffer value (β) Strength of pH buffering, in units of mol OH- dm-3
pH Temperature coefficient Change of pH with temperature, in pH units of K-1

Primary Standard Buffers

As there can be significant variations in the purity of samples of a buffer of the same nominal chemical composition, it is essential that the primary buffer material used has been certified with values that have been measured with Cell I. The Harned cell is used by many national metrological institutes for accurate measurements of pH of buffer solutions.

Typical values of the pH(PS) of the seven solutions from the six accepted primary standard reference buffers, which meet the conditions stated above, are listed in Table 2. Batch-to-batch variations in purity can result in changes in the pH value of samples of at most 0.003. The typical values in Table 2 should not be used in place of the certified value (from a Harned cell measurement) for a specific batch of buffer material.

The required attributes listed above effectively limit the range of primary buffers available to between pH 3 and 10 (at 25 °C). Calcium hydroxide and potassium tetraoxalate are excluded because the contribution of hydroxide or hydrogen ions to the ionic strength is significant. Also excluded are the nitrogen bases of the type BH+ (such as tris(hydroxymethyl)aminomethane and piperazine phosphate) and the zwitterionic buffers (e.g., HEPES and MOPS [Ref. 10]). These do not comply because either the Bates-Guggenheim convention is not applicable, or the liquid junction potentials are high. This means the choice of primary standards is restricted to buffers derived from oxy-carbon, -phosphorus, -boron and mono, di- and tri-protic carboxylic acids. The uncertainties (Ref. 11) associated with Harned cell measurements are calculated (Ref. 1) to be 0.004 in pH at NMIs, with typical variation between batches of primary standard buffers of 0.003.

Secondary Standards

Substances that do not fulfill all the criteria for primary standards, but to which pH values can be assigned using Cell I are considered to be secondary standards (Table 3). Reasons for their exclusion as primary standards include difficulties in achieving consistent and suitable chemical quality (e.g. acetic acid is a liquid), suspected high liquid junction potential, or inappropriateness of the Bates-Guggenheim convention (e.g., other charge-type buffers). The uncertainty is higher (e.g., 0.01) for biological buffers. Certain other substances, which cannot be used in cells containing hydrogen gas electrodes, are also classed as secondary standards.

Calibration Procedures

  1. One-point calibration
    A single-point calibration is insufficient to determine both slope and one-point parameters. The theoretical value for the slope can be assumed but the practical slope may be up to 5% lower. Alternatively, a value for the practical slope can be assumed from the manufacturer’s prior calibration. The one-point calibration therefore yields only an estimate of pH(X). Since both parameters may change with age of the electrodes, this is not a reliable procedure.
  2. Two-point calibration [target uncertainty: 0.02–0.03 at 25 °C]
    In the majority of practical applications, glass electrodes cells are calibrated by a two-point calibration, or bracketing, procedure using two standard buffer solutions, with pH values, pH(S1) and pH(S2), bracketing the unknown pH(X). Bracketing is often taken to mean that the pH(S1) and pH(S2) buffers selected from Table 2 should be those that are immediately above and below pH(X). This may not be appropriate in all situations and choice of a wider range may be better.
  3. Multi-point calibration [target uncertainty: 0.01–0.03 at 25 °C].
    Multi-point calibration is carried out using up to five standard buffers. The use of more than five points yields no significant improvement in the statistical information obtainable.
  4. Details of uncertainty computations (Ref. 11) have been given (Ref. 1).

Measurement of pH and Choice of pH Standard Solutions

  1. If pH is not required to better than ±0.05 any pH standard solution may be selected.
  2. If pH is required to ±0.002 and interpretation in terms of hydrogen ion concentration or activity is desired, choose a standard solution, pH(PS), to match X as closely as possible in terms of pH, composition and ionic strength.
  3. Alternatively, a bracketing procedure may be adopted whereby two standard solutions are chosen whose pH values, pH(S1), pH(S2) are on either side of pH(X). Then if the corresponding potential difference measurements are E(S1), E(S2), E(X), then pH(X) is obtained from
    pH(X) = pH(S1) + [E(X) – E(S1)]/%k
    where %k = 100[E(S2) – E(S1)]/[pH(S2) – pH(S1)] is the apparent percentage slope. This procedure is very easily done on some pH meters simply by adjusting downwards the slope factor control with the electrodes in S2. The purpose of the bracketing procedure is to compensate for deficiencies in the electrodes and measuring system.

Information to Be Given about the Measurement of pH(X)

The standard solutions selected for calibration of the pH meter system should be reported with the measurement as follows:

System calibrated with pH(S) = .... at ... K

System calibrated with two primary standards, pH(PS1) = .... and pH(PS2) = .... at .... K

System calibrated with n standards, pH(S1) = ...., pH(S2) = .... etc. at .... K


Interpretation of pH(X) in Terms of Hydrogen Ion Concentration

The defined pH has no simple interpretation in terms of hydrogen ion concentration but the mean ionic activity coefficient of a typical 1:1 electrolyte can be used to obtain hydrogen ion concentration subject to an uncertainty of 3.9% in concentration, corresponding to 0.02 in pH.



  1. Buck, R.P., Rondinini, S., Covington, A.K., Baucke, F.G.K., Brett, C.M.A., Camoes, M.F.C., Milton, M.J.T., Mussini, T., Naumann, R., Pratt, K.W., Spitzer, P., and Wilson, G.S. Pure Appl. Chem. 74, 2105, 2002. []
  2. Sørensen, S.P.L. Comp. Rend. Trav. Lab. Carlsberg 8, 1, 1909.
  3. Sørensen, S.P.L., and Linderstrøm-Lang, K.L., Comp. Rend. Trav. Lab. Carlsberg 15, 1924.
  4. BIPM, Com. Cons. Quantité de Matière 4, 1998. See also M.J.T. Milton and T.J. Quinn, Metrologia 38, 289, 2001. []
  5. Harned H.S., and Owen, B.B., The Physical Chemistry of Electrolytic Solutions, Ch 14, Reinhold, New York, 1958.
  6. Bates R.G., and Robinson, R.A., J. Soln. Chem. 9, 455, 1980.
  7. Bates R.G., and Guggenheim, E.A., Pure Appl. Chem. 1, 163, 1960. []
  8. International Vocabulary of Metrology – Basic and General Concepts and Associated Terms (VIM), Third Edition, JCGM 200:2012, BIPM, 2012.
  9. Bates, R.G. Determination of pH, Wiley, New York, 1973.
  10. Good, N.E. et al., Biochem. J. 5, 467, 1966. []
  11. Evaluation of Measurement Data — Guide to the Expression of Uncertainty in Measurement (GUM), JCGM 100:2008, BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML, 2008.

TABLE 1. Properties of Some Primary and Secondary Standard Buffer Substances and Solutions/(Primary Standards in Bold Face)

Salt or solid substanceFormulaMolality/mol kg–1Molar mass/g mol–1Density/g mL-1Amount conc. at 20 °C/mol dm–3Mass/g to make 1 dm3Dilution value ΔpH1/2Buffer value (β)/mol OH dm–3pH Temperature coefficient/K–1
Potassium tetroxalate dihydrateKH3C4O8·2H2O0.1254.1911.00910.0987525.101
Potassium tetraoxalate dihydrateKH3C4O8·2H2O0.05254.1911.00320.0496512.6200.1860.0700.001
Potassium hydrogen tartrate (sat at 25 °C)KHC4H4O60.0341188.181.00360.0346.40.0490.027-0.0014
Potassium dihydrogen citrateKH2C6H5O70.05230.221.00290.0495811.410.0240.034-0.022
Potassium hydrogen phthalateKHC8H4O40.05204.441.00170.0495810.120.0520.0160.00012
Disodium hydrogen orthophosphate (0.025 m) + potassium dihydrogen orthophosphate (0.025 m)Na2HPO4
Disodium hydrogen orthophosphate (0.03043 m) + potassium dihydrogen orthophosphate (0.00869 m)Na2HPO40.03043141.9591.00200.086654.3020.070.016-0.0028
Disodium tetraborate decahydrateNa2B4O7·10H2O0.05381.3671.00750.0498519.012
Disodium tetraborate decahydrateNa2B4O7·10H2O0.01381.3671.00010.009983.8060.010.020-0.0082
Sodium hydrogen carbonate (0.025 m) + sodium carbonate (0.025 m)NaHCO30.02584.011.00130.024922.0920.0790.029-0.0096
Calcium hydroxide (sat. at 25 °C)Ca(OH)20.020374.090.99910.020251.5-0.280.09-0.033

TABLE 2. Typical Values of pH(PS) for Primary Standards as a Function of Temperature (0–50 °C)

Primary standards (PS)0 °C5 °C10 °C15 °C20 °C25 °C30 °C35 °C37 °C40 °C50 °C
Sat. potassium hydrogen tartrate (at 25 °C)3.5573.5523.5493.5483.5473.549
0.05 mol kg–1 potassium dihydrogen citrate3.8633.8403.8203.8023.7883.7763.7663.7593.7563.7543.749
0.05 mol kg–1 potassium hydrogen phthalate4.0003.9983.9973.9984.0004.0054.0114.0184.0224.0274.050
0.025 mol kg–1 disodium hydrogen phosphate + 0.025 mol kg–1 potassium dihydrogen phosphate6.9846.9516.9236.9006.8816.8656.8536.8446.8416.8386.833
0.03043 mol kg–1 disodium hydrogen phosphate + 0.008695 mol kg–1 potassium dihydrogen phosphate7.5347.5007.4727.4487.4297.4137.4007.3897.3867.3807.367
0.01 mol kg–1 disodium tetraborate9.4649.3959.3329.2769.2259.1809.1399.1029.0889.0689.011
0.025 mol kg–1 sodium hydrogen carbonate + 0.025 mol kg–1 sodium carbonate10.31710.24510.17910.11810.06210.0129.9669.9269.9109.8899.828

TABLE 3. Values of pH(SS) for Some Secondary Standards as a Function of Temperature
(From Harned Cell I Measurements)

Secondary standards0 °C5 °C10 °C15 °C20 °C25 °C30 °C37 °C40 °C50 °C
0.05 mol kg–1 potassium tetroxalatea1.671.671.671.671.681.681.681.691.691.71
0.05 mol kg–1 sodium hydrogen diglycolateb3.473.473.483.483.493.503.523.533.56
0.1 mol dm–3 acetic acid + 0.1 mol dm–3 sodium acetate4.684.674.674.664.664.654.654.664.664.68
0.01 mol dm–3 acetic acid + 0.1 mol dm–3 sodium acetate4.744.734.734.724.724.724.724.734.734.75
0.02 mol kg–1 piperazine phosphatec6.586.516.456.396.346.
0.05 mol kg–1 tris hydrochloride + 0.01667 mol kg–1 trisc8.478.308.147.997.847.707.567.387.317.07
0.05 mol kg–1 disodium tetraborate9.519.439.369.309.
Saturated (at 25 °C) calcium hydroxide13.4213.2113.0012.8112.6312.4512.2912.0711.9811.71

  • aPotassium trihydrogen dioxalate (KH3C4O8).
  • bSodium hydrogen 2,2-oxydiacetate.
  • c2-Amino-2-(hydroxymethyl)-1,3 propanediol or tris(hydroxymethyl)aminomethane.

Page 1 of 1

Entry Display
This is where the entry will be displayed

Log In - Individual User
You are not within the network of a subscribing institution.
Please sign in with an Individual User account to continue.
Note that Workspace accounts are not valid.

Confirm Log Out
Are you sure?
Log In to Your Workspace
Your personal workspace allows you to save and access your searches and bookmarks.
Remember Me
This will save a cookie on your browser

If you do not have a workspace Log In click here to create one.
Forgotten your workspace password? Click here for an e-mail reminder.
Log Out From Your Workspace
Are you sure?
Create your personal workspace
First Name (Given)
Last Name (Family)
Email address
Confirm Password

Incorrect login details
You have entered your Workspace sign in credentials instead of Individual User sign in credentials.
You must be authenticated within your organisation's network IP range in order to access your Workspace account.
Click the help icon for more information on the differences between these two accounts.
Incorrect login details
You have entered your Individual User account sign in credentials instead of Workspace credentials.
While using this network, a personal workspace account can be created to save your bookmarks and search preferences for later use.
Click the help icon for more information on the differences between Individual User accounts and Workspace accounts.
My Account

Change Your Workspace Password
Current Password

New Password
Confirm New Password

Update your Personal Workspace Details
First Name (Given)
Last Name (Family)
Email address

Workspace Log In Reminder
Please enter your username and/or your e-mail address:

Email Address

Searching for Chemicals and Properties

The CRC Handbook of Chemistry and Physics (HBCP) contains over 700 tables in over 450 documents which may be divided into several pages, all categorised into 17 major subject areas. The search on this page works by searching the content of each page individually, much like any web search. This provides a challenge if you want to search for multiple terms and those terms exist on different pages, or if you use a synonym/abbreviation that does not exist in the document.

We use metadata to avoid some of these issues by including certain keywords invisibly behind each table. Whilst this approach works well in many situations, like any web search it relies in the terms you have entered existing in the document with the same spelling, abbreviation etc.

Since chemical compounds and their properties are immutable, a single centralised database has been created from all chemical compounds throughout HBCP. This database contains every chemical compound and over 20 of the most common physical properties collated from each of the >700 tables. What's more, the properties can be searched numerically, including range searching, and you can even search by drawing a chemical structure. A complete list of every document table in which the compound occurs is listed, and are hyperlinked to the relevant document table.

The 'Search Chemicals' page can be found by clicking the flask icon in the navigation bar at the top of this page. For more detailed information on how to use the chemical search, including adding properties, saving searches, exporting search results and more, click the help icon in to top right of this page, next to the welcome login message.

Below is an example of a chemical entry, showing its structure, physical properties and document tables in which it appears.

image of an example chemical entry
We use cookies to improve your website experience. To learn about our use of cookies and how you can manage your cookie settings, please see our Cookie Policy. By continuing to use the website, you consent to our use of cookies.
Cookie Policy

Cookie Policy

We have developed this cookie policy (the “Cookie Policy”) in order to explain how we use cookies and similar technologies (together, “Cookies”) on this website (the “Website”) and to demonstrate our firm commitment to the privacy of your personal information.

The first time that you visit our Website, we notify you about our use of Cookies through a notification banner. By continuing to use the Website, you consent to our use of Cookies as described in this Cookie Policy. However, you can choose whether or not to continue accepting Cookies at any later time. Information on how to manage Cookies is set out later in this Cookie Policy.

Please note that our use of any personal information we collect about you is subject to our Privacy Policy.

What are Cookies?

Cookies are small text files containing user IDs that are automatically placed on your computer or other device by when you visit a website. The Cookies are stored by the internet browser. The browser sends the Cookies back to the website on each subsequent visit, allowing the website to recognise your computer or device. This recognition enables the website provider to observe your activity on the website, deliver a personalised, responsive service and improve the website.

Cookies can be ‘Session Cookies’ or ‘Persistent Cookies’. Session Cookies allow a website to link a series of your actions during one browser session, for example to remember the items you have added to a shopping basket. Session Cookies expire after a browser session and are therefore not stored on your computer or device afterwards. Persistent Cookies are stored on your computer or device between browser sessions and can be used when you make subsequent visits to the website, for example to remember your website preferences, such as language or font size.

Cookies We Use and Their Purpose

We use three types of Cookies - ‘Strictly Necessary’ Cookies, ‘Performance’ Cookies and ‘Functionality’ Cookies. Each type of Cookie and the purposes for which we use them are described in this section. To learn about the specific Cookies we use, please see our List of Cookies.

1. Strictly Necessary Cookies

‘Strictly Necessary’ Cookies enable you to move around the Website and use essential features. For example, if you log into the Website, we use a Cookie to keep you logged in and allow you to access restricted areas, without you having to repeatedly enter your login details. If you are registering for or purchasing a product or service, we will use Cookies to remember your information and selections, as you move through the registration or purchase process.

Strictly Necessary Cookies are necessary for our Website to provide you with a full service. If you disable them, certain essential features of the Website will not be available to you and the performance of the Website will be impeded.

2. Performance Cookies

‘Performance’ Cookies collect information about how you use our Website, for example which pages you visit and if you experience any errors. These Cookies don’t collect any information that could identify you – all the information collected is anonymous. We may use these Cookies to help us understand how you use the Website and assess how well the Website performs and how it could be improved.

3. Functionality Cookies

‘Functionality’ Cookies enable a website to provide you with specific services or a customised experience. We may use these Cookies to provide you with services such as watching a video or adding user comments. We may also use such Cookies to remember changes you make to your settings or preferences (for example, changes to text size or your choice of language or region) or offer you time-saving or personalised features.

You can control whether or not Functionality Cookies are used, but disabling them may mean we are unable to provide you with some services or features of the Website.

First and Third Party Cookies

The Cookies placed on your computer or device include ‘First Party’ Cookies, meaning Cookies that are placed there by us, or by third party service providers acting on our behalf. Where such Cookies are being managed by third parties, we only allow the third parties to use the Cookies for our purposes, as described in this Cookie Policy, and not for their own purposes.

The Cookies placed on your computer or device may also include ‘Third Party’ Cookies, meaning Cookies that are placed there by third parties. These Cookies may include third party advertisers who display adverts on our Website and/or social network providers who provide ‘like’ or ‘share’ capabilities (see the above section on Targeting or Advertising Cookies). They may also include third parties who provide video content which is embedded on our Website (such as YouTube). Please see the website terms and policies of these third parties for further information on their use of Cookies.

To learn about the specific First Party and Third Party Cookies used by our, please see our List of Cookies.

Managing Cookies

You always have a choice over whether or not to accept Cookies. When you first visit the Website and we notify you about our use of Cookies, you can choose not to consent to such use. If you continue to use the Website, you are consenting to our use of Cookies for the time being. However, you can choose not to continue accepting Cookies at any later time. In this section, we describe ways to manage Cookies, including how to disable them.

You can manage Cookies through the settings of your internet browser. You can choose to block or restrict Cookies from being placed on your computer or device. You can also review periodically review the Cookies that have been placed there and disable some or all of them.

You can learn more about how to manage Cookies on the following websites: and

Please be aware that if you choose not to accept certain Cookies, it may mean we are unable to provide you with some services or features of the Website.

Changes to Cookie Policy

In order to keep up with changing legislation and best practice, we may revise this Cookie Policy at any time without notice by posting a revised version on this Website. Please check back periodically so that you are aware of any changes.

Questions or Concerns

If you have any questions or concerns about this Cookie Policy or our use of Cookies on the Website, please contact us by email to [email protected]

You can also contact the Privacy Officer for the Informa PLC group at [email protected].

Our Cookies

Here is a list of cookies we have defined as 'Strictly Necessary':

Taylor and Francis 'First Party' Cookies


















Here is a list of the cookies we have defined as 'Performance'.

'Third Party' Cookies

Google Analytics:





The Voluntary Product Accessibility Template (VPAT) is a self-assessment document which discloses how accessible Information and Communication Technology products are in accordance with global standards.

The VPAT disclosure templates do not guarantee product accessibility but provide transparency around the product(s) and enables direction when accessing accessibility requirements.

Taylor & Francis has chosen to complete the International version of VPAT which encompasses Section 508 (US), EN 301 549 (EU) and WCAG2.1 (Web Content Accessibility Guidelines) for its products.

Click here for more information about how to use this web application using the keyboard.

This is replaced with text from the script
This is replaced with text from the script
Top Notification Bar Dialog Header
Your Session is about to Expire!
Your session will expire in seconds

Please move your cursor to continue.