Heptane has nine isomers, or eleven if enantiomers are counted:
Heptane (n-heptane), H3C–CH2–CH2–CH2–CH2–CH2–CH3,
2-Methylhexane (isoheptane), H3C–CH(CH3)–CH2–CH2–CH2–CH3,
3-Methylhexane, H3C–CH2–C*H(CH3)–CH2–CH2–CH3 (chiral),
2,2-Dimethylpentane (neoheptane), H3C–C(CH3)2–CH2–CH2–CH3,
2,3-Dimethylpentane, H3C–CH(CH3)–C*H(CH3)–CH2–CH3 (chiral),
2,4-Dimethylpentane, H3C–CH(CH3)–CH2–CH(CH3)–CH3,
3,3-Dimethylpentane, H3C–CH2–C(CH3)2–CH2–CH3,
3-Ethylpentane, H3C–CH2–CH(CH2CH3)–CH2–CH3,
2,2,3-Trimethylbutane, H3C–C(CH3)2–CH(CH3)–CH3, this isomer is also known as pentamethylethane and triptane.