The ACS Style Guide

Effective Communication of Scientific Information

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➤➤➤➤➤ C H A P T E R 4

Writing Style and Word Usage

• Every writer has a personal style, but allgood writing tends to observe guidelinesand conventions that communicatemeaning clearly and exactly to readers.Scientific writing, in particular, must beprecise and unambiguous to be effective.

Verbs: Voice➤ Use the active voice when it is less wordyand more direct than the passive.

The fact that such processes are under strictstereoelectronic control is demonstrated byour work in this area.

Our work in this area demonstrates that suchprocesses are under strict stereoelectroniccontrol.

➤ Use the passive voice when the doer of theaction is unknown or not important or when youwould prefer not to specify the doer of theaction.

The solution is shaken until the precipitate forms.

Melting points and boiling points have beenapproximated.

Identity specifications and tests are not includedin the monographs for reagent chemicals.

Verbs: Tense

Abstract: past tenseTheory: present tenseMethods, Results: past tenseDiscussion: often alternates between pasttense (when discussing results of currentstudy: "we found") and present tense ("ourresults are consistent with" or "the theory ofnatural selection predicts that").

In general, these are the verb tenses typicallyused in the following sections of a researchpaper:

➤ Present and simple past tenses may both becorrect for results, discussion, and conclusions.

The characteristics of the voltammetric waveindicate that electron transfer occursspontaneously.

The absence of substitution was confirmed bypreparative‐scale electrolysis.

The use of present or simple past tense for results,discussion, and conclusions should be consistentwithin a paper.

➤ Simple past tense is correct for stating whatwas done, either by others or by you.

The solutions were heated to boiling.

We found that relativistic effects enhance thebond strength.

The structures were determined by neutrondiffraction methods.

➤ Present tense is correct for statements offact.

Absolute rate constants for a wide variety ofreactions are available.

Hyperbranched compounds are macro‐molecular compounds that contain a branchingpoint in each structural repeat unit.

Other Forms

➤ It is acceptable to use split infinitives to avoidawkwardness or ambiguity.

AwkwardThe program is designed to assist financially thestudent who is considering a career in chemistry.

betterThe program is designed to financially assist thestudent who is considering a career in chemistry.

AmbiguousThe bonded phases allowed us to investigatefully permanent gases.

BetterThe bonded phases allowed us to fullyinvestigate permanent gases.

Subjects and Subject–Verb Agreement

➤ Use first person when it helps to keep yourmeaning clear and to express a purpose or adecision.

Jones reported xyz, but I (or we) found ….

I (or we) present here a detailed study ….

My (or our) recent work demonstrated ….

To determine the effects of structure on photophysics, I (or we) ….

However, avoid clauses such as

“we believe”, 

“we feel”, and

“we can see”, as well as

personal opinions.

Sentence Modifiers

Sentence Construction and Word Order

➤ Use the proper subordinating conjunctions.

Parallelism (Equal grammatical rank)

Comparisons

Compare to vs Compare with➤ Use the verb “compare to” when similaritiesare being noted. Use “compare with” whendifferences are being noted. Only things of thesame class should be compared.

Compared to compound 3, compound 4 showsan NMR spectrum with corresponding peaks.

Compared with compound 3, compound 4shows a more complex NMR spectrum.

Idioms: should not be split

“different from”, “similar to”, “identical to”,“identical with”.

Incorrect: The complex shows a significantlydifferent NMR resonance from that ofcompound 1.

Correct: The complex shows an NMRresonance significantly different from that ofcompound 1.

Incorrect: Compound 5 does not catalyzehydrogenation under similar conditions tocompound 6.Correct: Compound 5 does not catalyzehydrogenation under conditions similar to thosefor compound 6.Exception: These idioms can be split if anintervening prepositional phrase modifies the firstword in the idiom.The single crystals are all similar in structure tothe crystals of compound 7.Solution A is identical in appearance with solutionB.

Phrases such as “relative to”, “as compared to”,and “as compared with” and words such as“versus” are also used to introduce the secondelement in a comparison. The things beingcompared must be parallel.

The greater acidity of nitric acid relative to nitrousacid is due to the initial‐state charge distribution inthe molecules.

The lowering of the vibronic coupling constants forNi as compared with Cu is due to configurationinteraction.

Correct Word Usage

Grouping and Comparison Words

➤ Use “respectively” to relate two or moresequences in the same sentence.

The excitation and emission were measured at360 and 440 nm, respectively.

(That is, the excitation was measured at 360nm, and the emission was measured at 440nm.)

➤ Use the more accurate terms “greaterthan” or “more than” rather than theimprecise “over” or “in excess of ”.

• greater than 50% (not in excess of 50%)

• more than 100 samples (not over 100samples)

• more than 25 mg (not in excess of 25 mg,not over 25 mg)

➤ Use “fewer” to refer to number; use “less”to refer to quantity.

• fewer than 50 animals

• fewer than 100 samples

• less product

• less time

• less work

➤ However, use “less” with number and unitof measure combinations because they areregarded as singular.

• less than 5 mg

• less than 3 days

• Scan rate was less than 100 mV/s.

Between vs Among➤ Use “between” with two named objects;use “among” with three or morenamed or implied objects.Communication between scientists and thepublic is essential.Communication among scientists, educators,and the public is essential.Communication among scientists is essential.

Commonly Confused Words and Phrases

• I, myself, and mePlease give a copy of the agenda to Anne and me, I, or myself?).

I myself checked the agenda.

Cheryl and (I or myself?) checked the agenda.

The agenda was checked by Barbara and (me or  myself?).

• “due to” vs “because of”

“Due to”: adjective, to modify a noun orpronoun, after “to be”.

“because of”: adverb, to modify verbs

1. His defeat was due to the lottery issue.

2. He was defeated because of the lottery issue.

Cutbacks due to decreased funding have left uswithout basic reference books.

The accuracy of the prediction is due to asuperior computer program.

Due to  Because of exposure to low level of lead, children can be at risk for developmental problems.

• “based on” vs “on the basis of ”

“based on” must modify a noun or pronoun

“on the basis of ” to modify a verb

The doctors’ new methods in brain surgerywere based on Ben Carson’s work.

On the basis of the molecular orbitalcalculations, we propose a mechanism thatcan account for all the major features of alkaliand alkaline earth catalyzed gasificationreactions. (not Based on …)

Our conclusions are based on these findings.Discrimination based on disability is illegal as wellas unjust.

These guidelines are based on our experience.

The movie is based on a novel.He was denied permission on the basis of hiscriminal record.

They have been ranked on the basis of theirperformance.

Entrants compete on the basis of speed.

He was hired on the basis of his experience.

The plan was decided on the basis of ourbudget.

Stop discrimination based on sex.

“assure”, “ensure”, and “insure”

To assure is to affirm; to ensure is to makecertain; to insure is to indemnify for money.

• He assured me that the work had beencompleted.

• The procedure ensures that clear guidelineshave been established.

• You cannot get a mortgage unless you insureyour home.

“affect”, “effect”, and “impact”

• “affect” (v, to influence, modify, or change)• “effect” (n, consequence, outcome, or result)• “Impact” (n, a significant effect)

The increased use of pesticides affects agriculturalproductivity.

The effect of the added acid was negligible.

The impact of pesticide use on health is feltthroughout the world.

“whether” vs “whether or not”

➤ Use “whether” to introduce at least twoalternatives, either stated or implied.

• I am not sure whether I should repeat theexperiment.

• I am not sure whether I should repeat theexperiment or use a different statisticaltreatment.

• I am going to repeat the experimentwhether the results are positive or negative.

Use “whether or not” to mean “regardless ofwhether”.

Incorrect• I am not sure whether or not to repeat the

experiment.

Correct• I am not sure whether to repeat the

experiment.

• Whether or not the results are positive, I willrepeat the experiment.

• Whether or not I repeat the experiment, I willprobably leave the laboratory late tonight.

“to comprise,” “to compose,” “is composed of”

“to comprise” = “to contain” or “to consist of ”

“to compose” = “to make up” or “to make”

The whole comprises the parts, or the whole iscomposed of the parts, but the whole is notcomprised of the parts.

Never use “is comprised of ”.

The water molecule comprises two atoms ofhydrogen and one atom of oxygen. √(The whole comprises the smaller parts.)

The water molecule comprises of two atoms ofhydrogen and one atom of oxygen. X(Do not use the word of with comprise.)

Two atoms of hydrogen and one atom of oxygencomprise the water molecule. X

• Mercury, Venus, Earth and Mars composethe inner planets.√

• Two atoms of hydrogen and one atom ofoxygen compose the water molecule. √

• USA is composed of 50 states. √

• The water molecule is composed of two atomsof hydrogen and one atom of oxygen. √

Use of “A” and “An”

“where” vs “in which”

“data” vs “datum”

Wrong: The data suggests that…Correct: The data suggest that …

Words and Phrases To Avoid➤ Omit empty phrases such as• As already stated

• It has been found that

• It has long been known that

• It is interesting to note that

• It is worth mentioning at this point

• It may be said that

• It was demonstrated that

➤ Omit excess words

Use single words instead of phrases

➤ Do not use contractions in scientific papers

Do not use the word “plus” or the plus sign as asynonym for “and”.

Incorrect: Two bacterial enzymes were used in alinked‐enzyme assay for heroin plus metabolites.

Correct: Two bacterial enzymes were used in alinked‐enzyme assay for heroin and itsmetabolites

Do not use “respectively” when you mean“separately” or “independently”.

Incorrect: The electrochemical oxidations ofchromium and tungsten tricarbonylcomplexes, respectively, were studied.

Correct: The electrochemical oxidations ofchromium and tungsten tricarbonylcomplexes were studied separately.

Avoid misuse of prepositional phrases introducedby “with”.

Poor: Nine deaths from leukemia occurred, withsix expected.Better: Nine deaths from leukemia occurred, andsix had been expected.Poor: Of the 20 compounds tested, 12 gavepositive reactions, with three being greater than75%.Better: Of the 20 compounds tested, 12 gavepositive reactions; three of these were greaterthan 75%.

Poor: Two weeks later, six more animalsdied, with the total rising to 25.

Better: Two weeks later, six more animalsdied, and the total was then 25.

Do not use a slash to mean “and” or “or”.

Incorrect: Hot/cold extremes will damage thesamples.

Correct: Hot and cold extremes will damagethe samples.

Replace “and/or” with either “and” or “or”,depending on your meaning.Incorrect: Our goal was to confirm the presence ofthe alkaloid in the leaves and/or roots.

Correct: Our goal was to confirm the presence ofthe alkaloid in the leaves and roots.

Also correct: Our goal was to confirm the presenceof the alkaloid in either the leaves or the roots.

Also correct: Our goal was to confirm the presenceof the alkaloid in the leaves, the roots, or both.

➤ Avoid using the word “recently”. Yourarticle or book may be available for a longtime. This word will make it look dated inlittle time.

PoorIt was recently found that these effectsenhance the bond strength.

BetterHarris and Harris (2006) found that theseeffects enhance the bond strength.

Gender‐Neutral Language

Instead of “man”, use “people”, “humans”,“human beings”, or “human species”,depending on your meaning.

Outdated: The effects of compounds I‐Xwere studied in rats and man.

Gender‐neutral: The effects of compounds I‐X were studied in rats and humans.

Outdated: Men working in hazardousenvironments are often unaware of their rightsand responsibilities.

Gender‐neutral: People working in hazardousenvironments are often unaware of their rightsand responsibilities.

Outdated: Man's search for beauty and truthhas resulted in some of his greatestaccomplishments.

Gender‐neutral: The search for beauty andtruth has resulted in some of our greatestaccomplishments.

Instead of “manpower”, use “workers”, “staff”,“work force”, “labor”, “crew”, “employees”, or“personnel”, depending on your meaning.

Instead of “man‐made”, use “synthetic”,“artificial”, “built”, “constructed”,“manufactured”, or even “factory‐made”.

Outdated: The principal investigator shouldplace an asterisk after his name.

Gender‐neutral: Principal investigatorsshould place asterisks after their names.

Gender‐neutral: If you are the principalinvestigator, place an asterisk after yourname.

Gender‐neutral: The name of the principalinvestigator should be followed by anasterisk.

Instead of “wife”, use “family” or “spouse”where appropriate.

Outdated: The work of professionals such aschemists and doctors is often so time‐consumingthat their wives are neglected.

Gender‐neutral: The work of professionals suchas chemists and doctors is often so time‐consuming that their families are neglected.

Outdated: the society member and his wife

Gender‐neutral: the society member and spouse

➤➤➤➤➤A P P E N D I X 9 ‐ 1Recommended Spelling List

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