64和弦只分为三种，第一种是终止四六和弦（cadential64）,第二种叫经过四六和弦（passing64),第三种叫辅助四六和弦（auxiliary64)。
三种和弦的区别：
终止四六和弦(cadential64)其实是appoggiatura64和弦的一种。终止四六和弦的进程永远为V64-53。而appoggiatura64还包括其他进程比如I64-53。
特征：低音保持不变。
经过四六和弦
特征:根音为经过音。和弦进程：X-X64-X6 或者X6-X64-X。总之就是一个三和弦和它的六和弦之间。
辅助四六和弦
特征：低音保持不变，通常还有一个声部保持不变。进程：X-X64-X。就是两个相同的三和弦之间。
| Auxiliary64 | ||||||
| Voice Parts | Chord Progression | |||||
| Soprano | 2 Parts Neighbouring, 1 Part Stationary | |||||
| Alto | ||||||
| Tenor | ||||||
| Bass | Stationary Only | |||||
| Harmony Choice | X | X64 | X | |||
| Passing64 | ||||||
| Voice Parts | Chord Progression | |||||
| Soprano | Passing or Neighbouring | |||||
| Alto | Passing, Neighbouring or Stationary | |||||
| Tenor | ||||||
| Bass | Passing Notes Only | |||||
| Harmony Choice 1 | X | X64 | X6 | |||
| Harmony Choice 2 | X6 | X64 | X | |||
| Cadential64 | ||||||
| Voice Parts | Chord Progression | |||||
| Soprano | May use other chords in function | 6th & 4th | 5th & 3rd | Main function chord in root position | ||
| Alto | ||||||
| Tenor | ||||||
| Bass | 1st | 1st | ||||
| Harmony Choice | IV/I | V64-53 | I/VI | |||
| Appoggiatura64 | ||||||
| Voice Parts | Chord Progression | |||||
| Soprano | May use other chords in function | 6th & 4th | 5th & 3rd | Main function chord in root position | ||
| Alto | ||||||
| Tenor | ||||||
| Bass | 1st | 1st | ||||
| Harmony Choice | IV/V | I64-53 | V | |||
passing 64和cadential 64在功能上都不属于自己本身的和弦，所以在和弦功能的分析时，都要写成它们所归属的和弦（通常和它们之后的和弦相似）。但是在写和弦类型的时候passing 64要标注自己本身的和弦而不能和和弦功能相同，cadential 64在标注和弦类型时则和自己的功能完全一样。
