'volatile person' is correct and can be used in written English.
You could use it to describe someone who is unpredictable and liable to sudden changes of behaviour or mood. For example, "He is a volatile person, so we never know whether he will be happy or angry when he arrives."
"But I'm a volatile person.
I'm not really a volatile person.
Asked about dealing with adversity and criticism, Mr. Goldin said: "Basically, I'm a volatile person.
Russell Brand has described himself as a "volatile person" after he lost his cool with a journalist in Downing Street.
"I'm a volatile person, so I'd go in and I would see she was in a state and I'd start screaming and shouting, and that doesn't help anybody".
Linda Stein, the punk-rock manager turned real estate broker who was found bludgeoned to death on Tuesday in her Fifth Avenue penthouse, was a vibrant and volatile person who aroused strong and often contradictory feelings in those who knew her, friends and colleagues said yesterday as the police struggled to find a motive in her killing.
Her social services tutor described her as the most volatile young person she had ever worked with.
SAN FRANCISCO (Reuters) - Groupon is going to wait at least a couple of weeks before launching the final phase of its initial public offering because regulators still have questions for the daily deals website and the stock market is too volatile, a person familiar with the situation said on Tuesday.
"MDMA is highly volatile in one person but not the next," says DEA spokesman Melvin Patterson.
A unique, volatile, handsome and charming person who was loved by so many who knew him.
Dunga's role in a campaign that ended a 24-year dry spell for Brazil in world football, which included being Romario's roommate and perhaps the only person the volatile Brazil striker admired more than himself, guaranteed his iconic status as a captain able to run a tight ship and inspire his troops.
