| Assignments | The compounds | ||||||||||||||
| (I) | (Ia) | (Ib) | (Ic) | (Id) | (II) | (IIa) | (IIb) | (IIc) | (IId) | (III) | (IIIa) | (IIIb) | (IIIc) | (IIId) | |
| υ(OH) | ---- | 3458 | 3447 | 3460 | ---- | ---- | 3407 | 3435 | 3429 | 3429 | ---- | 3466 | 3396 | 3447 | 3392 |
| υ(N4H) | 3306 | 3234 | 3230 | 3211 | 3300 | 3310 | 3237 | 3238 | 3305 | 3305 | 3310 | 3237 | 3238 | 3305 | 3305 |
| υ(N2H) | 3196 | 3181 | 3175 | 3174 | 3198 | 3196 | 3179 | 3180 | 3194 | 3197 | 3196 | 3220 | 3202 | 3200 | 3198 |
| υ(NH) | 3092 | 3111 | 3109 | 3100 | 3109 | 3111 | 3109 | 3111 | 3105 | 3111 | 3107 | 3115 | 3115 | 3109 | 3115 |
| CH-arom. | 3064 | 3055 | 3030 | 3046 | 3000 | 3005 | 3034 | 3053 | 3005 | 3007 | 3005 | 3032 | 3039 | 3001 | 3007 |
| CH-aliph. | 2940 | 2932 | 2941 | 2940 | 2940 | 2940 | 2980 | 2934 | 2938 | 2940 | 2940 | 2943 | 2938 | 2938 | 2940 |
| υ(C=O)/υ(NCO) | 1651 | 1595 | 1601 | 1593 | 1595 | 1657 | 1595 | 1599 | 1591 | 1599 | 1670 | 1595 | 1597 | 1595 | 1599 |
| Thioamide I [β(NH)/υ(CN)] | 1402 | 1422 | 1443 | 1425 | 1435 | 1400 | 1420 | 1431 | 1416 | 1440 | 1400 | 1418 | 1450 | 1418 | 1445 |
| Thioamide II [υ(CN)/β(NH)] | 1342 | 1398 | 1375 | 1362 | 1398 | 1341 | 1400 | 1400 | 1400 | 1400 | 1341 | 1368 | 1379 | 1377 | 1400 |
| δ(OH) | ---- | 1307 | 1306 | 1308 | 1308 | ---- | 1306 | 1310 | 1310 | 1308 | ---- | 1307 | 1319 | 1310 | 1308 |
| υ(C-O) | ---- | 1292 | 1287 | 1287 | 1246 | ---- | 1290 | 1219 | 1273 | 1246 | ---- | 1245 | 1232 | 1246 | 1246 |
| υ(N?N) | 902 | 934 | 941 | 924 | 924 | 902 | 935 | 945 | 924 | 925 | 923 | 975 | 960 | 966 | 964 |
| υ(C=S)/υ(C-S) | 831 | 755 | 756 | 777 | 775 | 814 | 743 | 772 | 777 | 777 | 827 | 755 | 775 | 777 | 773 |
| υ(M-O) | ----- | 505 | 500 | 495 | 490 | ----- | 493 | 501 | 490 | 490 | ----- | 500 | 490 | 492 | 495 |
| υ(M-N) | ----- | 415 | 420 | 415 | 417 | ----- | 421 | 428 | 418 | 421 | ----- | 415 | 425 | 421 | 415 |