EDIT
23rd letter of the Russian alphabet, corresponds to lower case U+445
Transliterates as /h/ (international ISO 9 standard) or as /kh/ (British BSI and American English ALA standards), e.g. Khrushchev
Pronunciation depends on ensuing vowel: followed by /i/, /e/ - [x] breathed (unvoiced) guttural, followed by /a/, /o/, /u/ - [ç] breathed palatal sound
In modern Russian (since the 20th century?) transcription of Latin (proper names, loan words), this letter replaces the Latin /H/ for the sound of which there is no Cyrillic letter, e.g. Хайд-Парк (Hyde Park), хоккей (hockey). Alternative or parallel forms use the letter Г (G), e.g. Клятва Гиппократа (Hippocratic Oath) or Голливуд / Холливуд (Hollywood).