Coordinating conjunctions link two or more elements that have the same grammatical function within the sentence. They serve to add ideas, contrast them, choose among them, distribute actions or relate correlating elements. In this group appear Adversative Conjunctions, Correlative Conjunctions and other coordinating values that maintain the independence of the joined parts.

Copulative conjunctions add similar elements, and the most common ones are y, e and ni. The form y changes to e when the following word begins with the i sound, as in padre e hijo. Ni coordinates negations and is often repeated to reinforce the negative sense.

IdeaIdea	EjemploExample
Y une palabras u oraciones del mismo tipo.And unites words or clauses of the same type.	Pan y queso.Bread and cheese.
E sustituye a y ante sonido i.E substitutes for y before a sound i.	Padre e hijo.Father and son.
Ni enlaza elementos negativos.Ni links negative elements.	No canta ni baila.He neither sings nor dances.

Adversative conjunctions express opposition or contrast between ideas, and among them stand out pero, mas, sino and sin embargo. Pero introduces a restriction or expected turn, while sino corrects a previous negation. Sino que appears when a conjugated verb follows, and mas is a formal or literary use of contrast less common in everyday conversation; to expand this contrast, consult Adversative Conjunctions.

IdeaIdea	EjemploExample
Pero expresa contraste entre dos ideas.Pero expresses contrast between two ideas.	Quería ir, pero llovió.I wanted to go, but it rained.
Sino corrige una negación anterior.Sino corrects a previous negation.	No compró pan, sino leche.He didn't buy bread, but milk.
Mas es una forma formal de contraste.Mas is a formal form of contrast.	Quiso hablar, mas guardó silencio.He wanted to speak, mas he kept silent.
Sin embargo marca oposición más enfática.Sin embargo marks a more emphatic opposition.	Era tarde; sin embargo, salió.It was late; however, he went out.

Disjunctive conjunctions present alternatives and require choosing between two or more options. The main forms are o and u, and the second appears before words beginning with the sound o or ho to avoid phonetic clash. This value is used with decisions, possibilities and questions of selection.

IdeaIdea	EjemploExample
O presenta una alternativa.O presents an alternative.	¿Té o café?Tea or coffee?
U sustituye a o ante sonido o.U substitutes for o before the o-sound.	Siete u ocho.Seven or eight.
La disyuntiva ofrece elección entre opciones.The disjunction offers a choice between options.	Vienes o te quedas.Are you coming or staying?

Distributive conjunctions distribute actions, states or elements among various options. They are formed with fixed pairs such as ya... ya, bien... bien and unos... otros, which present alternation or distribution without one part depending syntactically on the other. Their effect is to enumerate distributions, not to add or oppose.

IdeaIdea	EjemploExample
Ya... ya alterna dos posibilidades.Ya... ya alternates two possibilities.	Ya ríe, ya llora.Sometimes he laughs, sometimes he cries.
Bien... bien presenta alternancia regular.Bien... bien presents regular alternation.	Bien por aquí, bien por allá.Well here, well there.
Unos... otros reparte grupos o acciones.Unos... otros distributes groups or actions.	Unos descansan, otros trabajan.Some rest, others work.

Correlative conjunctions work in pairs and both parts are needed for the relationship to be complete. Common forms are not only... but also and tanto... como, which link equivalent elements or add cumulative information. This type of linkage is very close to Correlative Conjunctions, and requires parallelism between the two coordinated parts.

IdeaIdea	EjemploExample
No solo... sino también añade información.Not only... but also adds information.	No solo canta, sino también compone.Not only sings, but also composes.
Tanto... como une dos elementos equivalentes.Tanto... como unites two equivalent elements.	Le gustan tanto el té como el café.They like both tea and coffee.
La correlación necesita dos miembros relacionados.Correlation needs two related members.	No solo estudia, sino que trabaja.Not only studies, but also works.

In coordination, the joined elements must share grammatical category and similar function. They coordinate nouns with nouns, adjectives with adjectives, verbs with verbs and clauses with clauses. When that balance is broken, the sentence sounds irregular or incomplete, which is why parallelism is a central rule also in Comparative Conjunctions and Consecutive Conjunctions.

IdeaIdea	EjemploExample
Se coordinan elementos de la misma categoría.Elements of the same category are coordinated.	Compró pan y leche.He bought bread and milk.
Los adjetivos deben mantenerse en paralelo.Adjectives must remain in parallel.	Era alto y elegante.He was tall and elegant.
Las oraciones coordinadas conservan su estructura.Coordinated sentences preserve their structure.	Llegó temprano y salió tarde.He arrived early and left late.

Coordination with y and o is usually written without a comma between the joined elements, because the relationship is already clear. Before pero and sin embargo the comma is common, since these conjunctions introduce a change of orientation. In rapid speech, sometimes the conjunction is omitted and the pause serves its function, though in writing it is advisable to keep the explicit form.

IdeaIdea	EjemploExample
Y suele unir sin coma.And is usually joined without a comma.	Compró pan y queso.Bread and cheese.
O también suele ir sin coma.Or also tends to go without a comma.	¿Sales o entras?Are you leaving or entering?
Pero suele ir precedido de coma.But is usually preceded by a comma.	Quería ir, pero no pudo.I wanted to go, but I couldn't.
Sin embargo suele ir entre pausas.However usually goes between pauses.	Llegó tarde; sin embargo, participó.He arrived late; however, he participated.

Coordinating conjunctions organize the relationship between units that maintain syntactic independence. Some add information, others oppose, others choose and others distribute or correlate elements with a fixed structure. Mastery of y/e, ni, pero, sino, o u and the paired forms allows constructing more precise, natural and balanced sentences.