Оригинал

The solution became cloudy.

The construction you're referring to is called subject-verb inversion. In English, it involves reversing the typical order of the subject and the verb in a sentence. This inversion is often used for various reasons, including emphasis, formality, or stylistic preference.

Here are a few common situations where subject-verb inversion might be used:

Emphasis: Placing the verb before the subject can emphasize the action or condition of the subject.

Example: "In the garden stood a majestic oak tree."
Adverbial Phrases: In some sentences, especially those beginning with adverbial phrases (like "At the bottom," in your case), inversion is used for stylistic reasons.

Example: "On the table lay a letter."
Question Formation: In questions, the subject and verb are often inverted.

Example: "Are you coming to the party?"
Conditional Sentences: In certain conditional sentences, subject-verb inversion is used for formal or literary effect.

Example: "Had I known about the event, I would have attended."
In your original sentence, "At the bottom, there were the metallic copper precipitate and a brown precipitate," the inversion is used for stylistic reasons, emphasizing what is located at the bottom. It's a versatile construction that adds variety and emphasis to English sentences.