Recreating Index Behaviour

Question

I have an index which has size 12 GB , i reliazed that this index space is fragmented for that i decided to defragmente its space , what i did for the dfragmentation is as follows.
1) drop that index.
2) recreate the same index.
-Before dropping that index the tablepace of that index space usage was 89 % in Enterprise manager console tablespaces link.
-After dropping this index it reclaimed the space of this tablepace usage column from 89 % to 81 %, i.e it reduce the space to 8%.
-After recreating that index the space did not reuse recliamed space from that tablespace , it reduced the space of /orahome, where my datafiles reside.
Though recreating an index is not having the same space as before , it is occuping the space of 4 GB as before to 10 GB.Why recreating the index is consuming the space of /orahome though the space from index tablespace is reclaimed?

Answer 1

no i am recreating the index on the same tablespace from where i dropped.
This script (metadata) i got from PL/SQL developer before dropping that index , i used the same script after dropping the index.
create unique index WF_ITEM_ATTRIBUTE_VALUES_PK on WF_ITEM_ATTRIBUTE_VALUES (ITEM_TYPE, ITEM_KEY, NAME)
  tablespace APPS_TS_TX_IDX
  pctfree 10
  initrans 11
  maxtrans 255
  storage
    initial 128K
    next 128K
    minextents 1
    maxextents unlimited
    pctincrease 0
SQL> Drop index WF_ITEM_ATTRIBUTE_VALUES_PK
  2  /
Index dropped.
[prod1@uat1 ~]$ df -ha
Filesystem                      Size            Used           Avail           Use%           Mounted on
/dev/mapper/vgora-lvora             1.4T           1.3T              93G            94%           /orahome
SQL> create unique index WF_ITEM_ATTRIBUTE_VALUES_PK on WF_ITEM_ATTRIBUTE_VALUES
  2  (ITEM_TYPE, ITEM_KEY, NAME)
  3    tablespace APPS_TS_TX_IDX
  4    pctfree 10
  5    initrans 11
  6    maxtrans 255
  7    storage
  8    (
  9      initial 128K
10      next 128K
11      minextents 1
12      maxextents unlimited
13      pctincrease 0
14    );
Index created.
[prod1@uat1 bin]$ df -ha
Filesystem                           Size            Used           Avail           Use%      Mounted on
/dev/mapper/vgora-lvora                     1.4T            1.3T               85G              94%      /orahome