diff --git a/automol/graph/_1rmg.py b/automol/graph/_1rmg.py
index 17a84072..d84f0a50 100644
--- a/automol/graph/_1rmg.py
+++ b/automol/graph/_1rmg.py
@@ -13,7 +13,7 @@
 SYMBOL = pp.Word(pp.alphas, max=2)("symbol")
 UNPAIRED = pp.Suppress("u") + ppc.integer("u")
 PAIRED = pp.Suppress("p") + ppc.integer("p")
-CHARGE = pp.Suppress("c") + ppc.integer("c")
+CHARGE = pp.Suppress("c") + ppc.signed_integer("c")
 BOND_ORDER = pp.Char(BOND_ORDER_DCT.keys())("bond_order")
 BOND = pp.Suppress("{") + KEY + pp.Suppress(",") + BOND_ORDER + pp.Suppress("}")
 BONDS = pp.OneOrMore(pp.Group(BOND))("bonds")