Analogous to the description of iron pyrite, manganese diselenide is sometimes viewed as being composed of Mn2+ and Se22− ions, although being a semiconductor, MnSe2 is not appropriately described in formal oxidation states.
ɐnˈæləɡəs tə ðə dᵻskɹˈɪpʃən ʌv ˈaɪɚn pˈaɪɹaɪt, mˈæŋɡənˌiːz dˌɪsᵻlˈɛnaɪd ɪz sˈʌmtaɪmz vjˈuːd æz bˌiːɪŋ kəmpˈoʊzd ʌv ˌɛmˈɛn tˈuː plˈʌs ænd sˈiː twˈɛnti tˈuː mˈaɪnəs ˈaɪɑːnz, ɔːlðˈoʊ bˌiːɪŋ ɐ sˌɛmɪkəndˈʌktɚ, ˌɛmˈɛn sˈiː tˈuː ɪz nˌɑːt ɐpɹˈoʊpɹɪətli dᵻskɹˈaɪbd ɪn fˈɔːɹməl ˌɑːksɪdˈeɪʃən stˈeɪts.