When should i use each of the following to mean each other / one another when dealing with reciprocal verbs? Are any of these interchangeable?

Question

When should i use each of the following to mean each other / one another? Are any of these interchangeable?

1. uno al otro

2. uno a otro

3. el uno del otro

4. mutuamente

5. recíprocamente

6. entre sí

Answer 1

(1) and (2) differ from 3 in that they require a verb that takes the preposition "a", while (3) requires a verb followed by the preposition "de".

In turn, (1) and (3) differ from (2) in that the definite article (al otro, del otro) points to the singularity of "the other", while the absence of the article leads us to understand "otro" as "another (within a larger group)" in (2).

1. Los mellizos se miraban fijo (el) uno al otro. (The twins stared at each other.)

2. Los empleados se miraban uno a otro sin saber qué hacer. (The employees -- more than two -- looked at one another without knowing what to do.)

3. Los mellizos se reían (el) uno del otro. (The twins laughed at each other.)

While we say mirar a, we say reírse de.

"recíprocamente" and "mutuamente" suggest a one-to-one relationship, but the former sounds very formal and is mostly restricted to scientific statements.

Instead, "entre sí" can refer to two or more than two. Curiously, the preposition "entre" renders other prepositions unnecessary. Thus, while we say:

• Hablaban uno con otro.

we say:

• Hablaban entre sí.