Rainbow Quiz - Identify the personality - Week 28

Here is the next weekly "Rainbow" quiz , where I would be giving 7 clues (Hence the name Rainbow) about a personality. Try to discover the person in the least number of clues . You can either leave the answer as a comment / email me . Feedback/ suggestions welcome. Googling is not preferred but then its just for fun and so go ahead if you need to.

"X" is a versatile genius who lost his life in the most unfortunate circumstance.

clue # 1 : Born to a wealthy family in Paris, "X" inherited a large fortune when his mother died. He attended College in France studying chemistry, botany, astronomy, and mathematics.

clue # 2 : His devotion and passion for chemistry was largely influenced by Étienne Condillac, a prominent French scholar of the 18th century. He was an elected member of the French Academy of Sciences, France's most elite scientific society, at the young age of 25 for an essay on street lighting and in recognition for his earlier research in chemistry.

clue # 3 : Among his many achievements, he stated the first version of the Law of conservation of mass, co-discovered, recognized and named oxygen as well as hydrogen, disproved the phlogiston theory, introduced the Metric system, invented the first periodic table including 33 elements, and helped to reform chemical nomenclature.

clue # 4 :"X" was also an investor and administrator of the "Ferme Générale," a private tax collection company; chairman of the board of the Discount Bank (later the Banque de France); and a powerful member of a number of other aristocratic administrative councils ( Which later led to his downfall).

clue # 5 : "X" was one of the 28 French tax collectors and a powerful figure in the unpopular Ferme Générale. "X" was branded as a traitor after the French revolution. He was tried, convicted, and executed on the same day in Paris, at the young age of 51.An appeal to spare his life was cut short by the judge who stated: "The Republic has no need of geniuses"

clue # 6 : His importance for science was expressed by the mathematician Joseph Louis Lagrange who lamented the beheading by saying: "It took them only an instant to cut off that head, but France may not produce another like it in a century."

clue # 7 : One and a half years following his death, "X" was exonerated by the French government. When his private belongings were delivered to his widow, a brief note was included reading "To the widow of "X", who was falsely convicted."

Who is X?