Her Italian-language Wikipedia article has this about her (Google translation lightly edited): "She was the eldest daughter of General Nikolai Nikolaevich Raevsky, and of his wife, Sofia Alexaevna Konstantinova. She received excellent training at home. In May 1821 she married the commander of the 16th Infantry Division, General Mikhail Fyodorvich Orlov. They had two children: Nikolai Mikhailovich (1822-1886) and Anna Mikhailovna. The Decembrist uprising marked the end of her husband's career. He was arrested and spent six months at the fortress of Peter and Paul and was granted house arrest on his estate, with a ban on visiting the capitals. She returned to Moscow at the end of 1826 to say goodbye to her sister.
Ekaterina met Alexander Sergeyevich Pushkin in St. Petersburg in 1817, with whom she met often, discussing literature. After her husband's death, Ekaterina traveled a lot. She spent a lot of time organizing documents and archives describing the life and work of her great-grandfather, Mikhail Vasilyevich Lomonosov. She continued to be interested in literature and all that was written about Pushkin. She died on 3 February 1885 in Tsarskoye Selo. She was buried in the Novodevichy convent next to her husband."
