diff --git a/src/input_xml.f90 b/src/input_xml.f90
index c753ef7e87..779ba2816b 100644
--- a/src/input_xml.f90
+++ b/src/input_xml.f90
@@ -423,6 +423,7 @@ contains
     integer :: n
     real(8) :: val
     logical :: file_exists
+    character(3) :: default_xs
     character(MAX_WORD_LEN) :: units
     character(MAX_WORD_LEN) :: name
     character(MAX_LINE_LEN) :: filename
@@ -442,9 +443,15 @@ contains
        call fatal_error()
     end if
 
+    ! Initialize default cross section variable
+    default_xs_ = ""
+
     ! Parse materials.xml file
     call read_xml_file_materials_t(filename)
 
+    ! Copy default cross section if present
+    default_xs = default_xs_
+
     ! Allocate cells array
     n_materials = size(material_)
     allocate(materials(n_materials))
@@ -495,6 +502,26 @@ contains
        do j = 1, n
           ! Combine nuclide identifier and cross section and copy into names
           nuc => material_(i) % nuclides(j)
+
+          ! Check for empty name on nuclide
+          if (len_trim(nuc % name) == 0) then
+             message = "No name specified on nuclide in material " // &
+                  trim(int_to_str(m % id))
+             call fatal_error()
+          end if
+
+          ! Check for cross section
+          if (len_trim(nuc % xs) == 0) then
+             if (default_xs == '') then
+                message = "No cross section specified for nuclide in material " &
+                     // trim(int_to_str(m % id))
+                call fatal_error()
+             else
+                nuc % xs = default_xs
+             end if
+          end if
+
+          ! copy full name
           name = trim(nuc % name) // "." // trim(nuc % xs)
           m % names(j) = name
 
diff --git a/src/xml-fortran/templates/materials_t.xml b/src/xml-fortran/templates/materials_t.xml
index dbb939ac12..7ef52b2f15 100644
--- a/src/xml-fortran/templates/materials_t.xml
+++ b/src/xml-fortran/templates/materials_t.xml
@@ -15,8 +15,8 @@
   <!-- Type for specifying a nuclide -->
 
   <typedef name="nuclide_xml">
-    <component name="name" type="word" length="10" />
-    <component name="xs" type="word" length="3" />
+    <component name="name" type="word" length="10" default="''" />
+    <component name="xs" type="word" length="3" default="''" />
     <component name="ao" type="double" default="0.0" />
     <component name="wo" type="double" default="0.0" />
   </typedef>
@@ -38,5 +38,6 @@
   </typedef>
 
   <variable name="material_" tag="material" type="material_xml" dimension="1" />
+  <variable name="default_xs_" tag="default_xs" type="word" length="3" />
 
 </template>