NOVELTY - An electrolyte solution contains an ionic compound having a tricyano methide anion and a monovalent element-containing cation (1), and a nitrogen-containing organic compound (2) and/or a nitrogen-containing organic compound (3).    USE - Electrolyte solution is used for electrolytic capacitor (claimed). Uses include but are not limited to electrolytic capacitor, electrical double layer capacitor, solar cell, electrochromic display element, primary battery, secondary battery and fuel cell.    ADVANTAGE - The electrolyte solution provides electrolytic capacitor having low impedance characteristics and reduced product expansion during solder reflow.    DETAILED DESCRIPTION - An electrolyte solution contains an ionic compound having a tricyano methide anion and a monovalent element-containing cation of formula: Rs-LH+ (1), and a nitrogen-containing organic compound of formula (2) and/or a nitrogen-containing organic compound of formula: N(-R5)(-R6)(-R7) (3).    L=carbon, silicon, nitrogen, phosphorus, sulfur or oxygen, preferably nitrogen ;    R=monovalent element, functional group or organic group;    s=2, 3 or 4;    R1-R4=H, 1-8C hydrocarbyl, acetyl, alkoxy or carbonitrile;and    R5-R7=H or 1-8C hydrocarbyl.    When at least two of R1-R4 are hydrocarbyl groups, those hydrocarbyl groups may have a structure directly bonded. When at least two of R5-R7 are hydrocarbyl groups, those hydrocarbyl groups may have a structure directly bonded. An INDEPENDENT CLAIM is included for electrolytic capacitor. The electrolytic capacitor has a capacitor element (6) accommodated in a bottomed cylindrical exterior case to which the electrolytic solution is impregnated. The capacitor element is formed by winding an anode foil (1) and a cathode foil (2) through a separator. An electrode extraction lead is connected to the anode foil.    DESCRIPTION OF DRAWING(S) - The drawing shows an exploded perspective view of the aluminum electrolytic capacitor element.    Anode foil (1)    Cathode foil (2)    Separator (3)    Capacitor element (6)    Anode tab terminal (11)