Analysis of information sources in references of the Wikipedia article "Dmitri Mendeleev" in English language version.
Mendeleev seemed to have very few theological commitments. This was not for lack of exposure. His upbringing was actually heavily religious, and his mother – by far the dominating force in his youth – was exceptionally devout. One of his sisters even joined a fanatical religious sect for a time. Despite, or perhaps because of, this background, Mendeleev withheld comment on religious affairs for most of his life, reserving his few words for anti-clerical witticisms ... Mendeleev's son Ivan later vehemently denied claims that his father was devoutly Orthodox: "I have also heard the view of my father's 'church religiosity' – and I must reject this categorically. From his earliest years Father practically split from the church – and if he tolerated certain simple everyday rites, then only as an innocent national tradition, similar to Easter cakes, which he didn't consider worth fighting against." ... Mendeleev's opposition to traditional Orthodoxy was not due to either atheism or scientific materialism. Rather, he held to a form of romanticized deism.