Here's what rhymes with sigmatropic.
tropic topic atopic inotropic myopic isotropic psychotropic subtopic subtropic philanthropic anisotropic isotopic telescopic gyroscopic microscopic macroscopic endoscopic hygroscopic arthroscopic misanthropic stereoscopic fluoroscopic kaleidoscopic stroboscopic electroscopic spectroscopic submicroscopic Words that almost rhyme with sigmatropic
logic erotic biotic patriotic periodic chaotic neurotic biologic geologic melodic idiotic necrotic dialogic fibrotic meiotic nephrotic prosodic robotic cirrhotic aquatic exotic despotic episodic hypnotic narcotic neurologic pathologic psychotic etiologic symbiotic cathodic cytologic hematologic radiologic sclerotic unpatriotic ecologic rhapsodic haematologic gynaecologic antibiotic physiologic histologic morphologic psychologic semiotic spasmodic gynecologic hydrologic pedagogic quixotic serologic thrombotic demagogic xenophobic nonnarcotic aetiologic seismologic astronautic horologic immunologic pharmacologic antipsychotic homoerotic macrobiotic meteorologic epidemiologic posthypnotic atherosclerotic bacteriologic antispasmodic rollick chronic comic ionic ironic tonic folic gothic pyloric sonic boric conic frolic phonic strophic bionic hayrick placekick atomic cosmic toxic aortic garlic hydraulic caloric caustic chorionic colonic demonic genomic iconic euphoric formic gnostic iambic karmic laconic meteoric platonic bardic bucolic daemonic seraphic chopstick avionic carsick electronic symbolic metabolic embryonic harmonic anatomic autonomic tectonic carbolic metaphoric mnemonic parabolic phenolic sardonic synoptic yardstick anabolic anarchic anoxic basaltic diatomic lethargic polyphonic diabolic diatonic folkloric hierarchic subsonic telephonic vitriolic acrostic heartsick allegoric economic historic alcoholic apostolic philosophic catastrophic diastolic hegemonic prognostic systolic ultrasonic ascorbic hyperbolic metamorphic supersonic agnostic cathartic ganglionic histrionic nontoxic oligarchic polymorphic symphonic agronomic catatonic ergonomic gastronomic subatomic astronomic tragicomic hydroponic monophonic theosophic quadraphonic noncaloric shambolic chocoholic quadrophonic shopaholic acetonic chocaholic diagnostic hydrochloric prehistoric cytotoxic taxonomic melancholic orthodontic peristaltic uneconomic antarctic microcosmic subarctic workaholic sophomoric stereophonic infrasonic philharmonic nonalcoholic macroeconomic anthropomorphic architectonic socioeconomic microelectronic