ɪn ɹˈiːsənt jˈɪɹz, ɪt hɐz bɪkˌʌm ˈɛvɪdənt ðæt nˈuː pˈɑːlɪmˌoːɹfz ʌv ˌɛsˈɛn sˈiː ɛɡzˈɪsts bˈeɪst əpˌɑːn ðə kjˈuːbɪk ænd ˌɔːɹθoːɹhˈɑːmbɪk kɹˈɪstəl sˈɪstəmz, nˈoʊn æz pˈaɪˌɛsˈɛn sˈiː spˈeɪs ɡɹˈuːp: pˈiː tˈuːhˈʌndɹɪd θˈɜːtiːn, nˈoʊ. wˈʌnhˈʌndɹɪd nˈaɪnti ˈeɪt ænd ɡˈæməˌɛsˈɛn sˈiː spˈeɪs ɡɹˈuːp: pˌiːˌɛnˌɛmˈeɪ, nˈoʊ. sˈɪksti tˈuː
In recent years, it has become evident that new polymorphs of SnSe exists based upon the cubic and orthorhombic crystal systems, known as π-SnSe (space group: P213, No. 198) and γ-SnSe (space group: Pnma, No. 62)